Strength and Conditioning for Endurance Running E-Book

Richard Blagrove

• Herausgeber: Crowood
• Kategorie: Lebensstil
• Sprache: Englisch

Seitenzahl: 530

Veröffentlichungsjahr: 2015

Beschreibung

Endurance runners and coaches have tended to neglect weight training and conditioning techniques, often in the belief that they don't benefit performance, add unwanted muscle bulk, or cause excessive soreness. But as standards at elite level have improved, so coaches and runners have become increasingly keen on learning about the latest new training techniques or ways to stay injury free. No longer does the running community view strength and conditioning with scepticism, or as something that can only benefit elite runners. In Strength and Conditioning for Endurance Running, author Richard Blagrove shows how a strength and conditioning programme can directly improve running performance and reduce the risk of injury, as well as allowing an athlete to tolerate high volumes of running in the future. Fully illustrated with 312 colour images and diagrams.

Leseprobe

THE CROWOOD PRESS

First published in 2015 byThe Crowood Press LtdRamsbury, MarlboroughWiltshire SN8 2HR

www.crowood.com

This e-book first published in 2015

© Richard Blagrove 2015

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers.

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library.

ISBN 978 1 84797 988 9

Frontispiece: Shutterstock

Acknowledgements

Writing this book would not have been possible without the help and support of several important people. Firstly, I’d like to thank my colleagues at St Mary’s University for their assistance with this project and allowing me access to campus facilities for photo shoots. I am enormously grateful to my models Jo, Jake and Emily for the many hours they spent in the gym and outside, often in the freezing cold, shooting the photographs. A special thank you goes to Christine for her time and considerable patience in taking the photographs in each location. I’d also like to thank the endurance runners I’ve provided coaching support to over the last ten years. The experiences I’ve gained from working with you have provided me with the knowledge and confidence required to write this book. Finally, the most important thank you goes to my wife, Victoria. Without your support and understanding throughout this project, this book would never have come to fruition.

CONTENTS

Preface

Part 1: UNDERSTANDING YOUR NEEDS

  1     INTRODUCTION TO STRENGTH AND CONDITIONING

  2     PHYSIOLOGICAL PERSPECTIVES

  3     BIOMECHANICAL AND INJURY CONSIDERATIONS

  4     ASSESSING STRENGTHS AND WEAKNESSES

Part 2: STRENGTH TRAINING

  5     DISPELLING MYTHS

  6     RESISTANCE TRAINING

  7     PLYOMETRIC TRAINING

Part 3: CONDITIONING EXERCISES

  8     TRUNK TRAINING

  9     FOOT AND ANKLE CONDITIONING

10     HAMSTRING CONDITIONING

11     GLUTEAL STABILITY

12     TECHNICAL RUNNING DRILLS

13     MOBILIZATIONS AND STRETCHES

Part 4: ORGANIZING YOUR STRENGTH AND CONDITIONING

14     PLANNING YOUR TRAINING

15     CASE STUDY EXAMPLES

Index

Mo Farah competing in the London Marathon. (Photo: Shutterstock)

PREFACE

Running is arguably the most natural and pure form of physical exercise that the human body can be exposed to. Evolutionary studies suggest our ancestors were endurance runners who used persistence hunting to catch their prey, and the earliest evidence of competitive long-distance running events dates back to 1829BC. In the modern era, participation in endurance running events is at an all-time high, with thousands each year taking part in road-running events in particular, and many now attempting the holy grail of endurance running, the marathon. Dozens of new participation initiatives, charity fund-raising events and endurance challenges have also emerged over the last decade, and have contributed to the rise in popularity of the sport.

It is likely that if you are preparing for an endurance running event you have a goal in mind, whether it be to simply complete the distance, run a personal best or qualify for a major championship. In order to achieve that goal, hopefully you recognize that it is necessary to devise a training programme yourself, one that is carefully planned around the distance of the event and your individual requirements. Logically, your training programme should be predominantly made up of running-based training sessions of various distances, intensities and formats, each designed to enhance a specific feature of your physiology. Traditionally, though, endurance runners and coaches have tended to neglect other forms of training, such as weight training and conditioning techniques. This is perhaps due to a lack of guidance or instruction on which exercises are best to use, but often in the belief that they don’t benefit performance, add unwanted muscle bulk, or cause excessive soreness.

Despite the apparent uncertainty amongst many runners concerning the benefits of strength and conditioning, there does appear to be a growing awareness of its value. Coaches and runners are becoming increasingly keen on learning about the latest new training techniques or ways to stay injury free. Running magazines and the Internet are also littered with advice on the best workouts or exercises to improve running performance. No longer is the running community viewing strength and conditioning as only something élite runners include to give them an edge over their rivals. Despite the rising interest in strength and conditioning for runners, there is unfortunately a lack of high quality literature available. The main motivation for writing this book is therefore to provide a detailed resource for runners, coaches and students of strength and conditioning, that provides accurate and useful guidance.

The aim of this book is to share the knowledge I’ve gained, and the approach I’ve used, with the dozens of endurance runners for whom I have provided strength and conditioning support over the last ten years. The book is designed for any middle- and long-distance runner who is interested in learning about how to improve their performance and to lower injury risk with an evidence-based and scientific approach to their non-running-based training. Whether you plan to participate in a local fun run, or you are a young runner aspiring to compete at the Olympic Games, this book will provide you with a simple and effective set of supplementary exercises which you can tailor to your own individual requirements.

Best of luck with achieving the goal that you’ve set yourself. I hope you find that the information contained in this book adds a new dimension to your training, which will prove useful in helping you towards your goal.

KEY INFORMATION

These key information boxes are included throughout the book as a way of summarizing important information. If you are not interested in the scientific detail and are keen to get cracking with some S&C exercises, just read these boxes to ensure you receive the main messages from each section.

1

UNDERSTANDING YOUR NEEDS

To appreciate the underlying reasons why strength and conditioning training techniques are effective for endurance runners, it helps to have a basic understanding of endurance running physiology and biomechanics, Based upon the physical qualities that underpin endurance running and the risk factors that contribute towards injury, a set of suitable assessments can then be selected. These will allow you to identify your own strengths and weaknesses so you can tailor a training programme around your own individual needs. The opening section of this book aims to introduce basic scientific concepts associated with strength training, conditioning and endurance running before presenting a series of simple assessments.

CHAPTER 1: INTRODUCTION TO STRENGTH AND CONDITIONING

WHAT IS ‘STRENGTH AND CONDITIONING’?

Twenty years ago the term ‘strength and conditioning’ (S&C) was virtually unheard of, let alone an important element in the physical preparation of sports performers. As standards at an élite level have improved, investment into understanding the science that underpins performance has also increased. Consequently, over the last decade or so, the value of specialist sport science support has begun to be recognized, and S&C has developed into its own industry. Despite the modern professionalism of élite sport, the knowledge and experiences of specialist coaches working with full-time athletes is rarely filtered through to recreational sports performers and young athletes, who would also benefit from a more holistic approach to their sports preparation.

S&C is associated with any training methodologies that enhance the physical preparedness of athletes for their sports training and performance. This means that any training that isn’t directly set by the technical sports coach is considered S&C. In a broad sense, S&C has three primary goals: to improve performance, to improve the capacity for training, and to lower the risk of injury.

To improve performance: The training techniques described in this book are likely to result in a number of adaptations to the nervous and muscular systems, which will directly enhance your running performance. These include improvements in your ability to generate force with each stride, more effective use of elastic energy from tendons, and a more efficient running style.

To improve the capacity for training: An indirect benefit of additional physical training is that you will be able to tolerate a greater volume of running. Without a foundation of general athleticism, robustness and physical competence developed through S&C activities, it is very difficult to tolerate progressively higher loads of training over a long period of time.

To lower the risk of injury: Due to the high volumes of repetitive loading on the body and on the joints of the lower limb in particular, it is no surprise that endurance running has a high prevalence of over-use type injuries. Placing load through a tissue that is vulnerable to injury using specific strengthening exercises will result in improved tolerance to repetitive stress. Reducing injury risk also indirectly results in improved performance, as less training time is lost through being side-lined with an injury.

Education

An often forgotten objective of S&C is to educate athletes and their coaches on the importance of supplementary physical training. If, like many, the concepts and exercises addressed in this book are new to you, it is important that you understand why they are valuable to your running performance, and how they should be correctly carried out. Hopefully in this way, your ‘buy-in’ and engagement with an S&C programme will be much better. Improving awareness of S&C for young athletes is also particularly important both in terms of maximizing their potential and establishing good habits.

KEY INFORMATION

Strength and conditioning (S&C) involves any physical training activities outside of your running programme. Strength training has been shown to improve running performance and reduce the risk of getting injured. Improving basic movement skills and physical capacities will also allow you to tolerate higher volumes of running in the future.

WHAT IS ‘STRENGTH TRAINING’?

Many runners and their coaches will often associate the term ‘strength training’ with muscle-bound men pumping iron in the gym and grunting loudly! This obviously isn’t the outcome that an endurance runner wants, and neither does it have to be.

‘Strength’ is loosely defined as the highest amount of force that a muscle group can produce under specific conditions. Fundamentally, we all require a basic level of strength simply to move around and complete everyday tasks. Everything we do is underpinned by the ability of specific muscles to produce force during a co-ordinated movement. So if we want to start moving quickly, as when we run, we need the capacity to be able to produce a high level of force rapidly through this movement pattern. Running speed then ultimately is directly related to the amount of force you are able to produce against the ground during a short period of time, so if you want to learn how to run faster there is a logical reason to make your running muscles stronger!

The ‘Specificity’ Trap

The key phrase contained in the definition of strength above is that force is always expressed under ‘specific conditions’. This means that just because one person shows exceptional strength in a gym exercise, it doesn’t mean that they will be strong on a different skill, or, more importantly, be able to express force well during running. So strength is always specific to the movement pattern we are expressing force in, but also the speed and direction we are developing the force. With that in mind, it is important that when you select exercises to improve your strength, they carry a degree of ‘specificity’.

Being specific doesn’t mean simply replicating or mimicking the running action, but selecting the right tool for the job. Just because an exercise doesn’t resemble the running action, it doesn’t mean it is useless. In fact you’ll find that many of the exercises contained in the chapters of this book look nothing like running. However, each provides a specific overload to a physiological system or area of the body to drive a particular adaptive response. It is therefore important to think about the type of stress an exercise imposes upon the body and what outcome that stress will produce, rather than simply making sure it looks like running.

When it comes to strength training exercises, to ensure you achieve a degree of specificity that allows transfer to the running action, most exercises should involve the lower body producing a ‘triple extension’ movement pattern. Triple extension is a simultaneous extension of the ankle, knee and hip joints, such as when you jump in the air. Triple extension movements allow you to accelerate your body with a high level of force, exactly the same as in the running stride. Extending at these three joints in an explosive action not only takes advantage of the strong, powerful extensor muscles located in the lower limb, but also their ability to transmit force across the joints from hip, to knee, to ankle and through the ground.

There are a number of different types of strength that all reflect how force is being generated by the neuromuscular system. Luckily for us these are all very trainable qualities, which are important to running, and can be enhanced with the correct type of training.

KEY INFORMATION

Strength training involves improving your muscles’ ability to produce force. The training exercises used to develop strength should bear some similarity to the running action, but shouldn’t necessarily attempt to replicate a stride. Exercises should involve a movement pattern termed ‘triple extension’, which means your ankles, knees and hips should all extend simultaneously, like when you jump.

Maximum (or absolute) strength

Maximum strength is the quality that people usually associate with strength. It is the highest amount of force an individual can develop through a specific movement pattern, and so is best represented by the amount of weight you can lift on a given exercise. Powerlifters who can squat in excess of three times their bodyweight, and bench press twice their bodyweight, are examples of athletes who have a high level of maximum strength. Obviously strength of these magnitudes is of much less benefit to endurance runners, but this doesn’t mean that maximizing your strength isn’t important.

Relative strength

The maximum amount of force a muscle group can develop is related to both the size of the muscles contributing to a movement, and also the ability of the nervous system to activate as many muscle fibres as possible. Obviously an endurance runner’s performance would be negatively affected by adding any muscle bulk, so ‘specific’ maximum strength training should involve prescription, which teaches the nervous system to switch on more muscle fibres. This means that rather than maximum strength being the key quality, ‘relative strength’ is more important, as it represents the force that can be produced per kilogram of bodyweight.

Based upon the definition of maximum strength, improving this quality is best achieved by performing resistance-training exercises that use relatively heavy loads for a low number of repetitions. As Chapter 6 will address, loads used during key exercises must be individually prescribed. If you are new to this type of training, it is likely you will get stronger relatively quickly simply by practising technique with a moderate load.

KEY INFORMATION

There are several different types of ‘strength’ that are important for a runner to develop. Relative strength is the maximum force that you can generate per kg of body weight. Putting on muscle bulk is a disadvantage to endurance running performance; getting stronger without adding unwanted mass is important.

Explosive strength

The ability to generate a high level of force against the ground is an important determinant of running performance. However, during the running stride you spend only a fraction of a second in contact with the ground, therefore you have a limited amount of time to generate this force. So although strength is defined as the maximum amount of force you can generate, this definition doesn’t account for the fact that during running, force needs to be produced very rapidly. Producing strength quickly or explosively is a separate but very trainable quality that all runners need to develop to enhance their performance. Chapter 6 provides some key exercises that you can use to develop your explosive strength.

Reactive (or plyometric) strength

Of all the four main strength qualities defined here, reactive strength is undoubtedly the most important to the endurance runner. As explained later in this section, the running action relies heavily on the elastic properties of tendons and connective tissue to produce the majority of force. Instead of relying on the muscles to produce the force, which requires a considerable amount of energy, the body makes use of these passive tissues, which are incredibly efficient at storing and returning elastic energy. In much the same way as a spring, you can improve your body’s reactive strength qualities with a training technique called plyometrics. These exercises teach your legs to bounce along more effectively, and therefore muscles fatigue at a slower rate.

KEY INFORMATION

When you run, your foot is only in contact with the ground for a fraction of a second, giving your body very little time to produce force. Developing your ‘explosive strength’ will help you generate force more rapidly. During running, the tendons in your legs act like springs to help you move efficiently and save energy. Your ‘reactive strength’ is your ability to use these tendons effectively and can be improved with plyometric training.

WHAT IS ‘CONDITIONING’?

Although endurance runners will benefit from incorporating strength training into their programme, there is a whole range of other non-running based training activities that also offer benefits. In a broad sense, these are termed ‘conditioning’ activities. Conditioning can range from a simple stretching routine, to exercises designed to improve the integrity of a specific muscle or tendon in an area susceptible to injury.

Almost all exercises that can be considered ‘conditioning’ will bear very little resemblance to the running action. You may therefore feel they are simply not specific enough to be included in an S&C programme. However, it is important to bear in mind that in order to improve qualities such as posture, mobility, or the tolerance of a specific tissue to repeated loading, often a movement pattern or stimulus is required that doesn’t necessarily look or feel like running.

Corrective exercise programmes based upon the results of a movement screen also fall into the category of ‘conditioning’ exercises. Whether it’s a previous injury that has caused you to move incorrectly, or a bad habit you’ve picked up causing a muscle to become lazy, conditioning exercises should be integrated into your daily training routine to reduce the risk of injury.

KEY INFORMATION

Any exercises that don’t directly improve force-related qualities are termed ‘conditioning’ activities. These tend to be movements that have little similarity to the running technique but overload specific areas of the body to improve posture, technique or resilience to injury.

CHAPTER 2: PHYSIOLOGICAL PERSPECTIVES

When the objective of your sport is to run for an extended distance as fast as possible, there is no getting away from the fact that your heart and lungs need to be well developed to perform well. Many S&C training exercises will seem very ‘unspecific’ when compared to the movement patterns and energy demands associated with endurance running performance. It is therefore important to gain a clear understanding of the physical qualities that limit endurance running performance, so a sound rationale for the use of any non-running based training techniques can be developed.

Fig. 2.1: The main determinants of endurance running performance and the main physiological benefits that S&C can provide.

A considerable amount of scientific research has been conducted aimed at identifying the factors that may contribute towards becoming faster at distance running. These determinants are well documented in the literature, and include maximal oxygen uptake, fractional utilization, various thresholds on a lactate curve, and running economy. The best way to develop these qualities is obviously through specific running-based training, but other supplementary training may also contribute towards improvements in running speed. A summary of the main qualities that are important for endurance running performance and the physiological benefits that S&C offers is presented in Fig. 2.1.

MAXIMAL OXYGEN UPTAKE

For the running population at large, a physiological measure known as ‘maximal oxygen uptake’ (abbreviated to VO2max.) is widely recognized as the best predictor of performance from distances of a mile upwards. Put simply, your VO2max. is the highest amount of oxygen you can breathe in, transport to your working muscles, and use effectively to resynthesize the energy currency in your body, known as ‘adenosine triphosphate’ (ATP), to produce movement. For any given endurance running event that has participants of a wide range of abilities, VO2max. will generally be the best predictor of performance. In other words, the faster runners will have the highest VO2max. scores, the slowest will have the lowest VO2max. scores.

Given the importance of VO2max. to endurance running performance, it is crucial that strategies are used to develop this quality. Typically, runners will utilize a combination of high intensity interval training and long, slow distance running to develop their VO2max. and therefore improve their performance.

KEY INFORMATION

Your maximal oxygen uptake (known as your VO2max.) is a measure of how effectively you can use oxygen to produce energy while running. VO2max. tends to be an excellent predictor of running times over most endurance running distances, with faster runners possessing better VO2max. scores.

Implications for Strength and Conditioning

Increases in muscle mass will reduce performance

Although there is very little evidence to suggest that S&C activities will directly enhance the VO2max. of a runner, it is important to recognize that distance running performance is heavily dependent upon your body mass. This is particularly obvious if you consider that VO2max. is measured as the volume of oxygen that a runner can use per kilogram of their bodyweight per minute (written as ml/kg/min). Therefore any increase in muscle mass that may come from a weight-training programme will be detrimental to performance. As addressed in Chapter 5 of the book, the likelihood of a runner putting on muscle mass as a result of engaging in a regular routine of strength training is highly unlikely. The volumes of weight training and the frequency of sessions required to develop muscle mass are unnecessary for a runner, and far less time is taken to achieve the adaptations required to improve running performance.

Realizing your genetic potential

A runner’s VO2max. has a large genetic component, but runners who solely utilize a low intensity-based training approach to enhance VO2max. may never fully reach their aerobic potential. Although VO2max. represents the ceiling of your aerobic performance, the speed at which this is achieved is quite fast, at least in relative terms. This means that if you are unable to access the muscle fibres (called fast-twitch muscle fibres) that enable you to run at these faster speeds during interval-based training sessions, your VO2max. will never be developed to its full extent. Strength training has been shown to enhance recruitment of these fast-twitch muscle fibres, and therefore more will be accessible when there is a requirement to run faster. In essence, strength training will allow you to access ‘more gears’, which is crucial to maximizing your VO2max.

For the élite athlete who may often have to rely on their sprint finish, being able to access as many muscle fibres as possible is critical in the closing stages of a race. The difference between the fastest speed you can sprint at and your target race pace is often termed your ‘speed reserve’. Initially increasing this speed reserve by becoming stronger and using high intensity interval training should make your race pace feel relatively easier, and provide a greater buffer, which you can later tap into as you increase your training.

KEY INFORMATION

VO2max. is partly dependent upon your body weight. A well-designed weight training programme is unlikely to produce increases in muscle mass. The best way to enhance your VO2max. is to run fast during interval training sessions. Strength training will allow you to access more ‘fast twitch muscle fibres’, which will allow you to run faster during these interval training sessions.

FRACTIONAL UTILIZATION

Possessing a high VO2max. is crucial if you want to succeed as an endurance runner, but the speed at which you reach your VO2max. is somewhere around 3km race pace, or the speed you can sustain for no more than around ten minutes of running. So for distances of further than 3km, there are other important features of your physiology that are worth considering.

One quality that has been shown to be an accurate determinant of performance at longer distances, such as the marathon in particular, is called ‘fractional utilization’. This is a fancy way of describing the percentage of your VO2max. that you can sustain for a given distance. The best distance runners in the world have remarkably good fractional utilizations and are able to get to about 90 per cent of their VO2max., and then operate at this value for an hour or two. Lesser trained runners might perhaps be able to sustain 90 per cent of their VO2max. for around twenty minutes.

So if the event you’re aiming for is above 5km in distance, and particularly if you are a marathon runner, training for extended periods at your race pace to try and improve your fractional utilization will be of benefit. These types of medium to long continuous runs at a hard but sustainable pace are often called ‘tempo runs’ by running coaches.

Implications for Strength and Conditioning

Recruiting the correct type of muscle fibres

When we exercise, we are constantly required to produce, stabilize and control force. During running at sub-maximal speeds, our nervous system can choose to recruit different types of muscle fibre, which have different characteristics, to perform the same task. In untrained individuals, these recruitment patterns tend to be quite random, and as a result, muscle fibres are often used that are inappropriate for the task of running for long periods. If fast-twitch muscle fibres are recruited too early for moderate speed running, you will end up tiring quickly as these fibres have poor resistance to fatigue. Runners who can activate the correct types of muscle fibre for extended periods of time are more likely to be able to sustain their speed.

Recruiting the correct muscle fibres for the right job is a learned skill, known as ‘intra-muscular co-ordination’. Strength training results in adaptation to the nervous system, which helps the body select the most appropriate muscle fibres for a task. This allows you to control movement more effectively. In part, this explains why several scientific studies have found that strength training delays time to exhaustion at a sub-maximal running speed, because slow-twitch fibres are preferentially selected over fast-twitch fibres. So for the same fraction of your VO2max., strength training will enable you to run for a longer period of time.

Strength training improves co-ordination

One of the main adaptations you’ll not even notice as a result of performing a strength-training routine will be an improvement in coordination. This essentially means the nervous system gets much better at switching on muscles that are needed for movement and stabilization at the appropriate time, and switching off muscles that need to relax in a more timely fashion. So without even changing your technique, strength and plyometric training teaches your nervous system and muscles to behave better (known as ‘inter-muscular co-ordination’). This has also been suggested to be one of the benefits of running lots of miles: your technique becomes more engrained and your nervous system becomes better at producing the same repeated co-ordinated action. However, if you are new to running or a young athlete, running high mileages isn’t a safe or effective way of improving performance, so strength and plyometric training offers a means of fine tuning your nervous system without the added risk of suffering an injury.

KEY INFORMATION

The fraction of your VO2max. that you can run at for a given distance is another important predictor of your performance. Strength training will improve the co-ordination and timing of your muscles and nervous system. This allows you to use the right types of muscles fibres for the speed you run and move with more control, thereby improving this important quality.

LACTATE THRESHOLDS

Although maximizing VO2max. and fractional utilization should be your primary concern, there are other factors that play a part in determining performance. Whenever you start to move around more vigorously, as when we run, there is an increased requirement for energy, which is produced in our muscles from ATP. Unfortunately the body has a limited amount of ATP, so during exercise it uses a number of clever ways to maintain (or resynthesize) its supply. These are known as our energy systems, of which there are three main pathways, which attempt to help us maintain the speed we want to run at. Having a basic awareness of the main characteristics of these three energy systems is important to understanding how S&C might be beneficial to your physiology. The main features of these three energy systems are shown in Table 2a.

Energy system

Fuel

Rate of energy supply

Duration (seconds)

Typical activities

Phosphocreatine (anaerobic)

Phosphocreatine

Very fast

3–15

Sprint finish Resistance training Plyometrics

Anaerobic glycolysis

Glucose

Fast

15–180

Uphill running 200–600m intervals Circuit training

Aerobic

Carbohydrate and fat

Slow

>180

Long intervals Steady running

Table 2a: Main features of the three energy systems used to resynthesize ATP.

During very high intensity exercise, such as sprinting or lifting weights, ATP is primarily resynthesized by a substance called phosphocreatine, which is stored within muscle cells. Phosphocreatine is great at providing the energy for explosive and fast activities because it is readily available and can be used without oxygen (known as ‘anaerobic’), and is capable of producing huge bursts of energy. The down side, however, is that there is a very limited supply of phosphocreatine in the muscle, so for endurance performances this form of energy is only really important for sudden bursts of effort, such as a sprint finish.

If an extended period of high intensity effort is required, as in a 400m run or a long uphill drag in a cross-country race, the body must rely on another type of anaerobic energy. These types of effort are fuelled by energy from glucose, which is broken down from foods high in carbohydrate, and then stored in our muscles. Similar to the phosphocreatine pathway, oxygen isn’t required for glucose to maintain our ATP levels, so again energy is provided quite rapidly. The fancy word for this process is ‘anaerobic glycolysis’. The problem with our anaerobic glycolysis energy system is that instead of running out of energy supply, like the phosphocreatine system, we are limited by the waste products it produces that cause muscle fatigue. I’m sure you’ve all heard of a dreaded substance called ‘lactic acid’, which is one of the main by-products produced during anaerobic glycolysis. Lactic acid itself isn’t harmful, and doesn’t actually slow us down during high-intensity running efforts. But some of the substances that lactic acid splits into directly impair muscular contraction and cause those feelings of discomfort and pain.

One substance that is derived from lactic acid is ‘lactate’. This can be measured in the blood to indicate the extent to which we are using our anaerobic glycolysis system. Generally, the higher our levels of lactate, the more we are resynthesizing ATP without oxygen, so therefore the sooner we are likely to fatigue. In essence, blood lactate readings give us an idea of the degree to which we are relying on anaerobic metabolism, so how hard we are working during an endurance performance. The faster you run, the higher your blood lactate score will be, so the less likely it’ll be that you can sustain that level of effort for a long period.

For running distances of above about a mile, ATP is principally derived from the energy stored in our body (carbohydrate and fat), combined with molecules of oxygen. This is known as ‘aerobic metabolism’, and is the most important energy system for the endurance runner. Stressing this energy system regularly with long steady runs will certainly enhance how efficiently carbohydrate and fat are broken down in the presence of oxygen to maintain a plentiful supply of energy.

Importantly though, whenever you exercise all three of the energy systems described above are being used simultaneously. The degree to which each is being accessed mainly depends upon the intensity at which you run. On a slow jog, it is likely you are generating around 95 per cent of your energy from the aerobic system, because little energy is required and the body has sufficient time to allow oxygen to break down carbohydrate and fat. But if we speed up to 5km race speed, you require energy too rapidly for the aerobic system to cope fully, so around three-quarters of energy comes from aerobic sources, and the remaining 25 per cent must come from anaerobic energy pathways. At 5km running speed this means our blood lactate levels are much higher, so the speed is less sustainable.

Fig. 2.2: Graph showing a typical blood lactate response to running at different speeds.

Fig. 2.2 shows a typical ‘lactate curve’ for an endurance runner, which reflects the degree to which anaerobic metabolism is contributing as the speed of running increases. As running speed gradually climbs, lactate values in the blood start to rise, slowly at first but then in big jumps, as suddenly you can’t supply the energy that is required through aerobic means to sustain the faster speeds. There are a number of running speeds identified on the curve that correspond to those at which endurance runners will typically train and race. As well as VO2max., the speed at which a given lactate value is reached is an important and key predictor of performance.

An overriding objective of training is to shift this curve along the horizontal axis to the right, so a faster speed is being attained for the same lactate value. This is primarily achieved through interval training performed at running speeds around 10km pace and faster, and also ‘tempo’-type efforts at marathon up to 10km speed for periods of between 20 and 60min.

Implications for Strength and Conditioning

Improvement of anaerobic qualities

The main changes to your physiology that will result from S&C activities are related to your nervous system and muscles. However, once you begin a regular routine of S&C work, it will become apparent that most of the exercises used are executed at a higher intensity than most of your running training, and are performed in sets that usually last between 10 and 60 seconds.

A secondary but still important set of adaptations that you’ll gain from S&C activities therefore relate to improving how energy is metabolized anaerobically. The important quality that will improve relates to your ability to tolerate the waste products (or ‘metabolites’) that begin to build up in your muscles and cause fatigue when you are forced to use your anaerobic glycolysis pathway.

KEY INFORMATION

There are three ‘energy systems’ that maintain your energy supply during exercise. Two systems supply energy for high intensity activities without oxygen. The other uses oxygen to supply energy for lower intensity exercise, like endurance running. Most S&C activities are high intensity in nature so help to develop your energy systems that don’t use oxygen. This can help offset fatigue at faster running speeds, such as 5km where these systems contribute to a greater extent.

Because it is unlikely that you’ll be using running sessions that predominantly rely on anaerobic energy systems on a regular basis, S&C sessions are a useful strategy to ensure you still improve these anaerobic-related qualities. By improving your ability to clear waste products rapidly, this will also help your running performance. At speeds such as 5km and 10km speed where anaerobic contribution is quite large (seeFig. 2.2), an ability to deal with waste products becomes important.

RUNNING ECONOMY

Whereas VO2max. is the maximum amount of oxygen that you can use, running economy is essentially just the ‘VO2’ part. This is therefore defined as the amount of oxygen that is used at a given speed under VO2max. Logically it would appear that this shouldn’t be different between individuals, as it should require the same amount of energy per kilogram to move at a sub-maximal running speed. However, when VO2 is measured in a physiology laboratory, a wide range of values is found for different individuals. This suggests that this is a very important determinant of endurance running performance.

In fact, running economy appears to be the most important feature of your physiology to improve, particularly if you’ve been involved with the sport for a number of years. In groups of well trained runners, VO2max. scores are often quite similar, and more importantly are actually poor predictors of who will be the fastest at distances of over 5km. Oxygen consumption (VO2) at race speed provides a much more accurate impression of who is the superior runner, so finding strategies to obtain very low VO2 scores at sub-maximal speeds is key to becoming faster.

A wide range of factors influences running economy, including anthropometrics, gender, training background, footwear, bodyweight, technique and age. From a running perspective, both interval training performed at target race speeds, and long slow distance running are thought to aid in the development of running economy. Importantly, though, there is a large body of evidence that indicates that training techniques associated with S&C play an important role in enhancing running economy.

Implications for Strength and Conditioning

Strength training improves force-generating ability

The main benefit to engaging in a regular strength training routine will be an enhanced ability to generate force against the ground. By becoming stronger in exercises that involve extending through the ankle, knee and hip, such as squats and step-ups, your ability to exert force through similar movements will also improve. This will result in longer strides and therefore faster running speeds. As a result, your running economy will improve, as you will be able to run at a quicker speed without any added effort.

Improving running technique

You can probably recall dozens of times when you’ve watched a person running and cringed at how awkwardly they move! Having a poor running style on its own is unlikely to result in poor running economy at sub-maximal speeds, because each person adapts quite quickly to their own style. Importantly though, poor running mechanics is associated with a greater incidence of injury, so it is more important to address the issue from an injury risk perspective.

A poor running technique may, however, ultimately limit progress beyond a certain level of performance and prevent economical movement at faster speeds. For well trained runners in particular, improving elements of running technique is likely to reduce the oxygen cost of running. By learning how to prepare and move limbs into positions that will more effectively generate force and use elastic energy from tendons, running economy will be improved.

For young athletes in particular, developing a sound running action is particularly important. Developing good movement habits will offset the risk of injury in the long term, and ensure an efficient style that will support long-term development.

Using your tendons more effectively

During the running action, the elastic properties of tendons (particularly the Achilles tendon) and connective tissue contribute a substantial amount (around 30 to 40 per cent) of energy to propel you forwards. Unlike the muscular energy that is derived through the resynthesis of ATP, as described previously, the energy provided by tendons is free, so requires no additional fuel from dietary sources. Energy is stored and returned rapidly using a process known as the ‘stretch-shortening cycle’, explained in more detail in Chapter 7 (Plyometrics). Tendons, and to a lesser extent connective tissue, essentially behave like elastic bands: when stretched and released they return their energy at high velocity.

There are large differences between the extents to which runners use their tendons to contribute towards generating force. Runners who possess a greater level of elasticity in their tendons have more contribution from their stretch-shortening cycle to provide energy for movement, and therefore have a superior running economy. There is also a large body of scientific evidence to show that plyometric training (essentially jumping and hopping exercises) improves the ability of tendons to store and return energy effectively, thereby enhancing running economy.

KEY INFORMATION

‘Running economy’ describes how much oxygen you use at a given running speed. Particularly for well-trained runners, running economy is a very important determinant of performance. Several S&C activities have been shown to enhance running economy, including resistance training, which improves your stride length, and plyometric training, which improves the ability of your tendons to store and return elastic energy.

CHAPTER 3: BIOMECHANICAL AND INJURY CONSIDERATIONS

Running is one of the most fundamental and natural movement patterns a human can perform, yet running effectively requires a complex series of more simple movements that need to be integrated together with skill and good timing. If you read almost any running magazine or website, you won’t have to look far to find some sort of advice on how to improve your technique and run more efficiently. The problem with quite generic recommendations on how to run ‘correctly’ is that all runners will default to their most efficient style, partly based upon their anthropometric make-up and partly due to how they learned to run.

Although there is not necessarily a perfect way to run, there are certainly some common biomechanical characteristics that all effective runners possess. This chapter will describe the important kinetic (force-related) and kinematic (movement-related) aspects of a running stride, which provide a rationale for including specific S&C activities in an endurance runner’s training programme. The final part of this chapter also includes a section that considers the most prevalent endurance running-related injuries, and offers some basic guidance on how injury risk can be minimized.

THE PRODUCTION OF FORCE

The goal for most runners is to complete a given distance in the least possible time, so a good place to start when looking at the biomechanics of running is how we propel ourselves forwards at a faster rate. When considering how force is produced during running, a classic mistake that is often made by many coaches and runners, is to consider that running speed is the product of stride length and stride frequency, and they then attempt to directly enhance either one of these variables. Coaching cues such as ‘stride out’, or ‘quicken your stride tempo’, often do more harm than good by making runners work harder and therefore use more oxygen. The problem with describing running speed in this way, is that both stride length and frequency are the end outcomes of a multitude of factors, so every runner will self-optimize to find what works best for them. To understand how to run faster and more efficiently, we need to unpick the qualities that underpin stride length and frequency.

In general, stride length has a linear relationship to running speed, in that the faster you run, the longer the strides you will take. This isn’t achieved by actively reaching further forwards, nor is it a good idea to try and push off against the ground for longer. In fact the position of your foot when it hits the ground and as it leaves should be about the same, irrespective of running speed. The way that greater running speeds are actually achieved is by applying a higher level of force to the ground.

Fig. 3.1: Forces acting on the body during the running stride.

But why is applying vertical force so important if we want to move in a horizontal direction? The easiest way to understand this concept is by examining the forces that the body is being subjected to as we run, as shown in Fig. 3.1. The main external force acting upon the body at all times is gravity, therefore the only surface we have to apply force against in order to overcome gravity is the ground. When you initially break into a jog, in the first stride or two you’ll naturally lean forward and orientate your body at an angle to ensure you progress in a horizontal direction. The force you’ve applied is still predominantly vertical, though, it just appears to be horizontal because of the resultant motion you’ve created.

Once you’re jogging at a pace you’re comfortable with, you’ll notice your body comes upright, because you no longer wish to accelerate. To maintain this pace, all you need to do is simply keep overcoming the effect that gravity is having on your body! So each stride is like a mini vertical jump upwards, rather than a pull or push forwards.

There are also some small horizontal forces acting on you when you run, which represent the friction provided by the surface and air resistance. If friction is poor, as when you hit a muddy patch in a cross-country race or you are running into a howling gale, you’ll find you’ll naturally lean your trunk forwards slightly to give yourself more horizontal purchase against the ground and to apply more force against the wind. In any case, the ground is all you’ve got to work against because gravity is the main force that you need to overcome.

Fig. 3.2: Differences in force profiles between a runner moving slowly with a long ground contact time (A) and a runner moving quickly with a short ground contact (B).

Based upon this discussion, what do you have to do to become a faster runner and move at a faster pace from a biomechanical perspective? When jogging along at a comfortable pace, the ground is moving past you quite slowly, so you can get away with spending a long time on the ground to create the force needed to overcome gravity. This is shown in Fig. 3.2, as the curved line A. Here, enough force is applied to the ground to send you upwards against gravity, and you are moving along slowly enough to apply this force over a long period of time.

KEY INFORMATION

During running, the main force you need to overcome to keep moving forward at the same speed is gravity. If you want to run at a faster speed you need to apply a higher level of force to the ground in a shorter period of time.

When you start to speed up, the ground starts moving past you at a faster rate. So each time you hit the ground, to stop yourself braking and slowing down, you still need to produce enough force to overcome gravity but now in a far shorter period of time. This is represented by curved line B in Fig. 3.2, which has the same area under the curve as line A, so the same amount of total force is needed to overcome gravity. But the force is applied much faster, so both the peak and initial development of force application is much higher. Simply put, you need to apply more force against the ground in a shorter period of time.

MUSCLE CONTRACTIONS

Muscle contraction type

Definition

Key muscles during running

Concentric

Muscle produces force by shortening under tension

Gluteals, hamstrings and hip flexors

Eccentric

Muscle actively lengthens under tension

Hamstrings and calf

Isometric

Muscle produces force while remaining at same length

Quadriceps and calf

Stretch-shortening cycle

Moving rapidly from an eccentric to a concentric contraction to make use of stored elastic energy

Calf/Achilles tendon

Table 3a: Muscle contraction types and their occurrence during the running stride.

So if we accept that our running speed is mainly a product of how much and how rapidly force is produced during ground contact, we now need to consider the best way to produce this force. Muscles are capable of producing force in a number of ways, and these are summarized in Table 3a; each of these muscle contraction types is used at some point during the running cycle. It is the correct application and sequencing of various muscle actions that allows you to produce more force to run more quickly.

Fig. 3.3: Phases of a stretch-shortening cycle during running.

Fig. 3.3 shows where some of the main muscle actions that contribute towards propulsion occur, and how they combine to elicit an effective stretch-shortening cycle. As your foot strikes the ground, the majority of muscles in your lower limb immediately start battling against gravity to prevent your legs folding underneath you. Because you are fighting against gravity to push yourself back up (and into the next stride), the muscles around your ankles, knees and hips lengthen under a great deal of tension, known as an ‘eccentric contraction’. As you are not falling from a particularly big height from one stride to the next, the ankle and knee in particular will flex only slightly, and minimizing this collapse towards the ground is a key part of running faster.

KEY INFORMATION

There are three main types of muscle contraction that occur during the running stride: muscle lengthening under tension (eccentric), a static contraction (isometric) and a muscle shortening (concentric). When these contractions combine rapidly during the ground contact phase of the running stride, it is termed a ‘stretch-shortening cycle’.

The Achilles tendon, which attaches the calf to the heel, is a long, thick elastic structure that also stretches rapidly during the initial part of ground contact. This is an incredibly important element of the stretch-shortening cycle, as the Achilles is capable of storing large amounts of energy. The longer the distance over which the Achilles can stretch during the early part of ground contact, the more energy will be stored for later release.

Once the muscles have managed to halt your decent towards the ground, they then reach a point of transition known as the ‘amortization phase’, where they are briefly in an isometric or static state of contraction. Again, muscles contained in the calf complex and around the knee (plus deep stabilizers of the hip) are required to work particularly hard at this point. The energy absorbed in the Achilles tendon is waiting to be used, but it can only be stored there for less than a quarter of a second before it is dissipated as heat and is completely wasted. This is why springing right out of this bottom position of ground contact is so important: the free energy stored in your Achilles tendon won’t hang around for long!

From this isometric state, the muscles then begin to reverse their action and propel your body in the direction you want to go, which is upwards. This means the majority of the muscles of the lower limb begin to actively shorten, a process known as a ‘concentric contraction’. One of the key muscles capable of delivering high levels of force at this point is the strongest muscles in the body, the gluteals, located in the buttocks. The hamstrings are also important here as they also contribute with an explosive concentric contraction, and direct push-off horizontally in the late stance phase. Many endurance runners possess weak gluteals, so rely heavily on their quadriceps to help propel them forwards during the concentric phase. Although the quadriceps are quite strong in their own right, these runners are not optimizing this crucial phase of the running pattern. Muscles around the hips, particularly the gluteals, play several other important roles during running; these are highlighted in Chapter 11.

The concentric phase is also where the energy stored in the Achilles tendon is used to contribute to force production. Whereas the concentric action of the muscles requires energy fuels and oxygen to perform their work, the energy acquired from the Achilles tendon is returned for free. Runners who use their Achilles tendons effectively are able to obtain around half their force from the energy stored in each cycle. Runners who are poor at controlling eccentric forces and move into the concentric phase slowly, will characteristically carry their hips quite low and seem to spend a long time in contact with the ground. They utilize very little elastic energy, so are forced to use muscular work to a greater extent. S&C activities will improve how well you use your stretch-shortening cycle, both in terms of the structural qualities of muscles and tendons, plus learning how to place your legs in positions to better access these qualities.

As you increase your running speed and you are required to produce force in a shorter period of time, the demand to move from an eccentric to a concentric regime of muscular work also increases. It is therefore crucial that your muscles (particularly those around the ankle and knee) are able to withstand higher eccentric muscle forces and can ‘switch on’ rapidly, in order to reach a state of isometric tension quickly. When you observe most of the top endurance runners in the world, they are capable of doing this very well. This means they use energy from their tendons more effectively and therefore have superior running economy.

KEY INFORMATION

During the running stride, when the foot strikes the ground muscles work eccentrically. It is at this point that energy is stored in tendons. When you push off the ground, muscles around the hips work concentrically and the energy stored in tendons is also released to help propel you forward.

The Implications for Strength and Conditioning

Hopefully it is fairly obvious that there are potentially large benefits to be gained by incorporating S&C activities into your training to make you a faster runner. Based upon the discussion of how force is produced during the running action, there are several important physical qualities and muscle groups that should be targeted during S&C sessions.

The Achilles tendon: This tendon has a large potential to store and return energy during each stride to contribute to force production. The stiffer the Achilles tendon, the more likely it is to contribute effectively, as it will essentially spring back more rapidly. Weight training exercises that directly load the Achilles tendon, and more importantly plyometric training, will enhance this stiffness quality.

The calf and quadriceps muscles: The extent to which the Achilles tendon is used to generate force is in part dependent upon how well the muscles around the knee anchor its position to provide a stable base. In this way the Achilles tendon (rather than the muscles) stretches over a greater distance, allowing it to store more elastic energy. It is therefore important that the calf and the quadriceps muscles in particular can activate and withstand rapid rates of eccentric loading to reach high levels of isometric tension. This is one of the principal reasons why many studies that have used progressive programmes of plyometric training have shown such positive outcomes on running economy.

The gluteals and hamstrings: These are known as the ‘posterior chain’, and play an important role in the correct positioning of the foot at ground contact; they also provide force generation during the propulsive phase of ground contact. Weight-training exercises with relatively heavy loads that involve hinging at the hip such as squats, deadlifts and hip thrusts will strengthen these muscles.

Explosive force: An ability to generate high force in the muscles of the lower limb is obviously important, but developing high levels of force is only useful in running if it can be produced rapidly, which is a separate and highly trainable quality. It is also crucial to include explosive strength exercises that particularly emphasize hip extension, and recruitment of the posterior chain.

KEY INFORMATION

S&C activities can have a beneficial impact upon the stretch-shortening cycle to make you a faster runner. Plyometric training improves the ability of your Achilles tendon to store and release more elastic energy. Resistance training exercises improve muscles’ ability to hold the knee in a strong position during ground contact and increase the force generated from the muscles around your hips.

RUNNING TECHNIQUE

The points addressed in the sections above that relate to generating force have disregarded the actual movements involved in running to some extent. S&C activities that directly improve the neuromuscular qualities important for running are probably the most valuable, and will give you the biggest ‘bang for your buck’. Even if your technique remains unchanged, you are still likely to enhance your performance and may even indirectly improve your style.

Very few endurance running coaches will pay close attention to a runner’s technique, considering it to be natural and a fixed part of an athlete’s make-up. To a degree, this is true. But running is like any other sport: a series of skills that need to be learnt or improved. Attempting to make subtle changes to your technique over time is beneficial for a number of reasons:

*

A poor running style places unnecessary stress on your joints. Correcting faulty running mechanics and compensations is likely to reduce the risk of injury

*

Although your default running technique is likely to be your most efficient, improving your style over a long period of time will waste less energy, and therefore enhance your running economy

*

Although strength-training techniques are likely to directly improve your performance, working on placing your limbs in the correct positions will allow you to utilize these qualities more effectively. Don’t allow poor running form to hold back your speed

*

Incorporating technical running drills into your training programme or as part of a warm-up acts as a form of conditioning in its own right. By focusing on a particular aspect of your running movement with a particular set of drills, specific muscles and structures around joints will be stressed more than usual, making them more resistant to injury. See Chapter 12 for descriptions of suitable running drills

Fig. 3.4: Phases and key technical markers of the running stride.

Although everybody runs slightly differently, the key markers of effective running technique that should be consistent in all runners are shown in Fig. 3.4. Although the phases of a running stride are broken down here for ease of understanding, it is difficult to examine skills in a discrete or isolated manner. It is important to realize that each movement you execute impacts upon the next, so an error in one phase will have knock-on consequences for other actions.

KEY INFORMATION

Every runner has a slightly different style but there are some important technical points you should try to achieve when running that will prevent you wasting energy and reduce stress on areas vulnerable to injury.

Early Swing (Recovery) Phase

This brief description of the running action begins at ‘toe off’, which is the moment your foot leaves the ground and starts its recovery. From this position, the initial action of your thigh being pulled forward is brought about by a set of muscles at the top of your thigh known as the hip flexors. These muscles tend to become very over-worked and tight in runners, which can often pull you into a poor posture. So as well as keeping these muscles strong and well conditioned, it is important that you regularly mobilize your hip in extended positions to prevent poor posture (seeChapter 13). Several of your hip flexor muscles attach to your spine, so many of the exercises that involve flexion at the hip in the trunk-training chapter (8) will strengthen these muscles.

Recovering your heel close to your buttocks is an efficient way to move, as the arc your heel travels through is much shorter, therefore creating a shorter lever and less distance to travel. However, a tight heel position is mainly the result of a reflexive action around your hip, as your hip flexors contract rapidly to pull your foot off the ground. This action is probably best described as a sling, where the speed of the knee moving forwards whips the heel tight to your body. So rather than actively attempting to pull your heel up using the hamstrings (and drills such as heel flicks), you should be focusing on effectively flexing at the hip to pull the thigh into a front position.

KEY INFORMATION