Podcast, Science and Physiology, Training

Gareth Sandford, PhD | EP#398

 July 10, 2023

By  Bernardo Gonçalves


Gareth Sandford - That Triathlon Show

Gareth Sandford, PhD, is a physiologist at the Canadian Sports Institute Pacific. He has worked across 15 individual and team sports within three Olympic systems (UK, New Zealand and Canada) and three professional sports leagues (English football, cricket and rugby), supporting over 400 athletes that achieved 18 Olympic, Paralympic and World Championship medals and one world record. In this interview we discuss athlete profiling using the Anaerobic Speed Reserve, and how to optimise the training process for different types of athletes.

In this episode you'll learn about:

  • Athlete profiling and testing
  • Endurance, Hybrid, and Speed profiles and their unique characteristics
  • What is the Anaerobic Speed (Power) Reserve, and its underlying determinants?
  • How to improve sprinting speed or peak power
  • When and how to train for strengths and weaknesses
  • Why doing a lot of high intensity training can hinder rather than help the athlete
  • Critical Speed (Power) training

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Gareth's background

03:35 -

  • I am a sports science consultant specialising in sports that require a combination of high-speed and high-endurance capabilities. 
  • This includes team sports, middle-distance sports, and sports with elements of surging and finishing sprints. Originally from the UK, I studied at Loughborough University, where I gained experience through a placement with Chelsea Football Club and coaching sprints at Loughborough. 
  • I also worked with the triathlon setup, including GB development squads.
  • To further expand my knowledge, I travelled to India and the US, working with Altis under the guidance of Coach Dan Path and Stu McMillan. 
  • In 2015, I moved to New Zealand and delved into the programming of speed and endurance for athletes of varying abilities and specialities. 
  • This journey involved collaborating with over 80 coaches and 200 athletes worldwide, collecting PhD data and conversing with coaches to understand their challenges in balancing speed and endurance.
  • Eventually, I spent time in Canada, where I completed my PhD and worked on various aspects of running, including pacing, biomechanics, and technology. 
  • Currently based in Victoria, British Columbia, I continue to work as a postdoc researcher, focusing on wider aspects of running. 
  • I collaborate with team sports coaches and practitioners alongside my research, particularly in return-to-play scenarios.
  • I assist in programming speed and endurance training while emphasising the importance of individualisation based on athletes' unique needs and abilities.
  • Recreationally, I am actively involved in football (five-a-side), track and field, and cricket during the summer.
  • Every sport presents unique challenges. 
  • Although I specialised in the 800 meters for my PhD, I work with various sports. 
  • For example, yesterday, I was working with rowing and swimming, I'll be with athletics this afternoon, and tomorrow I'll focus on boxing. It's a diverse range of sports.
  • However, the common thread among the sports I work with is the combination of speed and endurance. Despite the technical and tactical differences, the underlying challenge is often more similar than people realise.

Sports where speed and endurance are important

08:25 -

  • There is a sliding scale of the relative balance between speed and endurance in triathlon, particularly in the one to ten-minute duration. 
  • Athletes can approach this duration from either the speed or endurance perspective and remain competitive. 
  • Significant surges and repeated sprints require specific underlying factors in races like sprints and Olympic distance triathlons.
  • During these moments, the ability to generate and transmit power becomes crucial. 
  • Force, technical, and coordination components efficiently apply force to the pedals or ground to increase speed. 
  • While energy system support is needed for repeated efforts, the limitation in these moments is not the energy supply but the ability to rapidly generate force and change force expression.
  • One challenge in training for these moments is having a balanced focus on both endurance and speed. 
  • Coaches and support staff must recognise that focusing solely on one aspect leaves potential untapped in critical race-defining moments, such as sprint finishes and surges. 
  • Success at the highest level requires understanding an athlete's balance between speed and endurance and maximising their strengths. 
  • This ability to leverage their unique qualities sets athletes apart in key race moments. It's important to note that success is not solely determined by maximal peak power but by finding the right balance between speed and endurance.

Athlete profile

12:34 -

  • I focus on collecting two key measures to understand the speed-endurance balance in a training group. 
  • The first measure is the maximal sprinting speed or peak power, assessed through a 50-meter sprint for running and a 10-second all-out sprint on the bike, taking the highest three-second average as the maximal peak power. 
  • This measure is crucial as it reflects an athlete's ability to generate force and utilise effective technique, which is important for successful surges during training.
  • The second measure is maximal aerobic speed or power (MAP/MAS). 
  • To estimate MAP, I employ a six-minute effort in the running, typically equivalent to a 2km time trial. 
  • This method correlates closely to the velocity of VO2 max in the lab, with a strong correlation coefficient of around 0.96 or 0.97. 
  • The six-minute duration is selected to align with the intensity at which VO2 max is typically reached. 
  • Prolonged efforts slightly above critical power can eventually lead to reaching VO2 max. 
  • Still, I focus on training the VO2 max stimulus with appropriate intensity variations between VO2 max and moderate critical speed/power.
  • By using these two physiological landmarks, we can assess an individual's general energy system competency, as well as their technique and force capabilities. 
  • This information helps to identify the unique qualities and contributions each athlete brings to the training group. Just as Dajo Sanders' work in professional cycling reveals variability even in endurance-dominant sports lasting days or weeks, we recognise that different individuals may require different training approaches. 
  • It prompts us to question whether everyone should receive the same training and how training should be tailored across different intensities.
  • Considering only one aspect, whether it's endurance or speed, may not fully address an individual's specific strengths and weaknesses. 
  • By understanding an athlete's capabilities, we can better cater to their needs and optimise their training program accordingly.

Testing the profile of athletes

17:24 -

  • When considering athletes' development in endurance sports, it is crucial to address the importance of maximising sprinting speed and power alongside aerobic capacity. 
  • Focusing on aerobic strength may be sufficient at lower levels, but to reach higher levels and podium performances, the ability to sprint becomes a differentiating factor.
  • Coaches face the challenge of developing sprinting qualities while balancing the high training volume characteristic of endurance sports. Learning sprinting technique is best done when athletes are fresh, as it involves coordination and motor patterns. 
  • In New Zealand, they introduced sprint training for development athletes aged 16 to 18 to enhance their overall performance.
  • The technical side of sprint training focuses on balance, range of motion, coordination, stride length, stride frequency, and avoiding energy-wasting movement patterns. 
  • On the strength-based side, it involves assessing maximal force production, force application, rate of force development, and stiffness for effective force generation and reactive capabilities.
  • Developing these qualities can occur through sprinting, weight training, physiotherapy, and practice. Establishing a foundation in these areas enables athletes to incorporate all-out sprints into their training regimen. 
  • Low-level plyometrics, such as jump rope exercises, can help with force application, while hills are a forcing function to improve technical positions and push into the ground.
  • These training approaches may not always feel like speed training, but they enhance the ability to express force. These improvements impact sprinting speed and contribute to running economy by optimising the muscle-tendon unit and overall efficiency throughout various intensities.

Improving sprinting ability

23:33 -

  • Considering and optimising all factors contributing to sprinting speed is crucial, including technical and strength-based elements. 
  • The extent to which these determinants are maximised directly impacts the potential improvement in sprinting speed. 
  • In a 12-week block focused on sprinting speed, junior athletes experienced an average 14% improvement in their sprinting speed, which is a substantial enhancement.
  • The importance of this improvement lies in its relation to the endurance aspect of the sport. 
  • Understanding the sprint ceiling and maximal aerobic speed or power is vital, as it affects the percentage of the anaerobic speed or power reserve utilised during efforts above VO2 max.
  •  Comparing two athletes with the same speed or power at VO2 max but differing maximal peak power (e.g., 1600 watts vs 1200 watts) provides insight into the relative exertion cost. 
  • For instance, if both athletes are required to exert 1000 watts during a sprint or surge, the athlete with a higher power reserve operates at a lower percentage of their reserve than the athlete with a lower power reserve.
  • This percentage of anaerobic power or speed reserve reflects qualities, including energy system cost (aerobic and anaerobic), buffering capacity, and neuromuscular and mechanical contributions. 
  • Moreover, it influences the recovery potential following an effort. An athlete operating at a lower percentage of their anaerobic reserve can repeat and recover from such efforts more effectively than an athlete operating at a higher percentage.
  • As athletes progress to higher performance levels, such as world-class competition, the minimum requirement for maximal peak power becomes standard among competitors. 
  • The ability to operate at a lower percentage of this power reserve, combined with durability built through aerobic conditioning, proper nutrition, and the neuromuscular and mechanical qualities to tolerate repeated surges, becomes crucial for success in races' final stages.
  • However, maximising sprinting speed is often overlooked in many middle and long-distance runners, hindering the possibility of optimising anaerobic speed or power reserves. 
  • Establishing a strong foundation through the development of sprinting speed is necessary before considering strategies to lower the percentage of anaerobic reserves and improve performance. 
  • This approach is being applied in short-track speed skating, where variability in performance profiles and leveraging individual profiles play a significant role in achieving optimal performance. 
  • Athletes with a larger anaerobic speed or power reserve can work at higher reserve percentages. In comparison, endurance-dominant profiles operate at lower percentages due to their higher max aerobic speed or power.
  • Ultimately, this challenges the notion that there is only one way to achieve success or a specific training model for different event types. 
  • The findings extend beyond a single sport, as similar patterns are observed in running, rowing, cycling, swimming, and team sports. 
  • Even in triathlon, traditionally associated with endurance profiles, there is diversity among athletes, highlighting the need to recognise and leverage individual performance profiles.

Process for classifying athletes

31:01 -

  • During a triathlon training session focused on threshold work, a coach and I observed three athletes completing six sets of 1200 meters. 
  • As we watched them trackside, we noticed that the workload varied for each athlete. 
  • For one athlete, 1200 meters seemed too challenging. For another, it appeared suitable, and for the third, it seemed too easy, requiring an extension to 2 kilometres.
  • One athlete had a hybrid profile based on performance, likely leaning towards Super League or Olympic distance events. 
  • The second athlete demonstrated a pure Olympic distance profile, while the third athlete had the potential to excel in longer ultra-distance races. 
  • This distinction between hybrid, endurance, and endurance-plus individuals became evident in their day-to-day training.
  • It was crucial to recognise these differences and adapt the training accordingly. 
  • Instead of all athletes completing the same six sets of 1200 meters, it was important to address their unique needs. 
  • This approach aimed to maximise each athlete's potential based on their capabilities and strengths.

Critical speed/power

33:11 -

  • It is important to keep the process simple yet based on a scientific rationale when testing and profiling athletes. A straightforward test such as a six-minute time trial or estimating critical speed can provide valuable information for athletes in isolated training situations. 
  • Critical speed can be estimated as a percentage of the maximal aerobic speed in team sports where laboratory facilities are unavailable.
  • However, it is crucial not to get overly fixated on the testing. Testing serves two purposes: establishing initial thresholds and determining appropriate training sessions to target those qualities. 
  • The focus should then shift to monitoring and executing the training sessions effectively. 
  • This involves assessing steady-state physiology, managing perceived effort, and monitoring variables like heart rate and lactate.
  • Relying on a single marker may not comprehensively understand an athlete's adaptation. 
  • Different adaptations have distinct timeframes, with high-intensity training affecting central adaptations like heart rate and breathing, while lower-moderate intensity work influences peripheral adaptations in the blood. 
  • Monitoring the intersection of breathing, perceptual response, heart rate, and lactate provides a more holistic assessment of threshold and adaptation progress.
  • The aim is to progress and adapt quickly, ensuring that athletes continue to improve rather than stagnate based solely on test results. 
  • By moving from testing to training and closely monitoring progress, athletes can avoid overdoing sessions and build the necessary endurance and adaptation. 
  • It is crucial to bridge the gap between intention and execution, as this is where many athletes can falter.

Prescribing a session based on the Aerobic Speed Reserve

39:46 -

  • When considering an athlete's sprinting speed or maximal peak power, it is crucial to recognise that these characteristics reflect their unique mechanical and neuromuscular qualities. 
  • Failure to account for these differences in training prescription can lead to workload discrepancies above the VO2 max. 
  • For example, prescribing a session at 110% of the maximal aerobic speed (MAS) could result in one athlete working at 20% of their anaerobic speed reserve while another works at 40%.
  • To address this issue, it is essential to prescribe workloads based on a percentage of the athlete's reserve. 
  • By doing so, the differences in stimulus experienced by each athlete can be reduced, promoting more equitable training responses. 
  • Over time, this approach prevents overstimulation or under-stimulation of the athletes, as the prescribed stimulus aligns more closely with their capabilities.
  • Taking into account these individual factors becomes crucial when evaluating training outcomes. 
  • If an athlete does not respond as expected, it is important to consider whether the applied stimulus was appropriate for their specific needs and qualities.

Improving your anaerobic speed/power reserve

42:30 -

  • One myth I want to address is that being fast doesn't solely come from high-intensity training. 
  • Regarding maximal peak power and sprinting speed, it is not limited by energy systems but rather by technique and force. 
  • It is important to understand that during the early phases of a training season, where training volume is being built up, it is unnecessary to constantly engage in high-intensity speed endurance intervals that spike lactate levels.
  • Instead, it is crucial to tap into the three to six-second all-out power alongside developing lower and moderate-intensity training, such as critical speed and threshold work. 
  • This can be achieved through activities like sprinting, but it should also focus on foundational elements that support maximal power and speed. Improvements can be seen by emphasising these foundational aspects before incorporating high-intensity training.
  • Although high-intensity training is valuable, it should not be performed every week with a significant physiological stress goal. 
  • It is essential to approach training like building a bank account, where low and moderate-intensity work represents deposits, while high-intensity sessions, races, or travel act as withdrawals. 
  • Careful consideration must be given to when and how often withdrawals are made to ensure optimal performance.
  • Building speed at the top end can be achieved by emphasising the underlying factors that support maximal three to six-second power and speed. This can start in the weight room, through physiotherapy and treatment, then progress to include hill training and sprinting.
  • When considering speed and intensity in training, there is a crucial interplay between the reserve capacity and the endurance at a specific intensity. 
  • For example, in a submaximal step test, two individuals may have the same threshold power or speed. However, during subsequent training sessions, one person may be able to sustain that intensity for a longer duration, while the other may fatigue sooner. 
  • This highlights the importance of both the reserve capacity and the training of endurance at that intensity.
  • The training approach should involve building a supportive framework that includes sprinting speed, max aerobic speed, and critical speed. This framework serves as the scaffolding for performance. 
  • Specific training periods are dedicated to developing the necessary endurance at race pace, focusing on metabolic and physiological adaptations. 
  • Throughout the rest of the year, training at that intensity may have more mechanical and technical goals rather than physiological aims.
  • This approach ensures that athletes are consistently prepared and close to their peak fitness level. 
  • By having a strong foundation of sprinting speed, a connection with race pace, and a well-developed aerobic system, athletes can maintain a full "bank account" of aerobic capacity without depleting it through excessive high-intensity training. 
  • This allows for more substantial intensity volumes when needed, resulting in a greater training stimulus and long-term growth. 
  • The gradual building and layering of training adaptations over time are vital components of this approach.

Profiling process

47:27 -

  • Step one involves conducting a 50-meter sprint test to determine sprinting speed and a six-minute run to establish the maximum aerobic speed (MAS), which provides the aerobic speed reserve (ASR).
  • As a screening process, I calculate the ratio of sprinting speed to MAS to evaluate the speed endurance balance within my squad. 
  • This helps identify athletes who may be dominant in one area or lacking balance between speed and endurance.
  • Based on the athlete's profile and goals, I establish benchmarks for key variables such as MAS, maximal aerobic power (MAP), maximal sprint speed, and maximal peak power. For example, achieving a certain MAP in wattage in Olympic Triathlon is essential for top performance.
  • Achieving the minimum benchmarks becomes crucial, especially for athletes aspiring to compete at the highest levels. 
  • Maximising their capacities and pushing towards the performance levels required to achieve their goals is important.
  • Beyond the initial profiling, the focus shifts to daily monitoring. This involves assessing how the athlete responds to training across different intensities. The goal is to deepen our understanding of their strengths and weaknesses and adapt the training accordingly.
  • Training sessions are adjusted based on the individual's response and characteristics. For example, if an athlete demonstrates strength in endurance during a threshold session, we may focus on further developing that aspect to maximise their performance potential.
  • The training approach emphasises leveraging an athlete's strengths while addressing weaknesses. This is especially crucial during championships, where athletes rely on their strengths to perform at their best.
  • We prioritise understanding each athlete on a physiological and technical level. By recognising who they are as individuals, we can tailor the training process to optimise their potential.
  • It is essential to align the athlete's profile, sports demands, and goals. This involves threading the needle and finding the right balance between training volume, specific profiles, and performance expectations.
  • In addition to addressing energetic factors, we also pay attention to neuromuscular speed and power, as these elements contribute to achieving the desired performance levels.

Focusing on athlete weaknesses

52:45 -

  • Regarding development stages, it's important to consider the long-term goals. If the aim is to potentially reach the Olympic podium in five, six, seven, or eight years, the focus should be on building the foundational blocks necessary for elite performance. 
  • Prioritising race results and immediate performance outcomes may hinder the development of the capacities and qualities required for long-term success.
  • While racing has its importance, such as providing tactical exposure and improving bike handling skills, it should be approached selectively during certain periods. The primary focus should be building capacities and qualities that underpin super-elite performance. 
  • This involves dedicating time to develop durability and maintaining performance even after significant energy expenditure.
  • Building these capacities takes time and requires a long-term perspective. 
  • It involves compounding the aerobic system over the years, allowing it to grow and strengthen without constantly making withdrawals due to frequent racing. 
  • It's about prioritising capacity development rather than solely focusing on immediate performance outcomes.
  • It's not an either-or situation but rather a careful selection of priorities between building capacity and racing for performance, depending on the desired long-term goals.

Training structure for different profiles

55:21 -

  • When considering training intensity, it is crucial to tailor the approach based on the specific athlete's endurance or speed-based profile. 
  • The endurance-focused athletes thrive with threshold-type efforts that flood the aerobic system, emphasising steady-state training for extended periods. 
  • VO2 max intervals can also be incorporated for highly trained individuals in endurance profiles. 
  • However, pushing these athletes into hard anaerobic sessions can be detrimental as their muscle machinery is not optimised for anaerobic glycolytic energy production.
  • On the other hand, speed-oriented athletes, particularly those who prefer anaerobic glycolytic energy production due to their fast-twitch muscle fibres, can tolerate and benefit from harder anaerobic training sessions. 
  • They possess higher baseline buffering capacity and anaerobic enzyme activity, making them more suited for anaerobic system demands.
  • Speed-oriented athletes require careful consideration when approaching very high-intensity or sprinting speed training due to the high central nervous system demand and the expression of large forces. 
  • Prescriptions should focus on managing the volume and frequency of such sessions. 
  • Even for endurance or hybrid athletes, a few exposures with five to six maximal efforts at three to six seconds of power per week are sufficient, as the goal is to maximise reserve and lower the percentage of anaerobic speed or power utilised.
  • Regarding integration and decision-making, discussions with coaches trackside revolve around the desired additional efforts, the upcoming training schedule, and where the intensity fits on the endurance-to-speed spectrum. 
  • Understanding the cost of the stimulus for endurance and speed-based profiles allows for informed decisions on training direction and balancing the training load accordingly. 
  • Ultimately, the goal is to optimise energy systems and sprinting speed, improving race pace performance during peak competition phases.

Triathlete test profile

1:00:55 -

  • When considering critical power testing and its outputs, it is important to understand the elements of performance that it addresses. The critical power model primarily focuses on energetics and is most applicable in cycling, where there is less variability than running. 
  • However, the model may not accurately account for these differences when comparing critical power tests between individuals with different biomechanics and mechanical efficiency.
  • Additionally, solely relying on an energy system model can overlook other determinants of performance. It is beneficial to approach performance from a broader perspective, considering the continuum of speed to endurance and power to endurance. 
  • When developing training programs, addressing maximal sprint speed, maximal aerobic speed, critical speed, and critical power at different points within the training week is essential. 
  • Separating the model itself from its underlying principles is crucial.
  • While critical speed and power are useful concepts, it is important not to become overly tied to the model's estimations of anaerobic capacity. 
  • The anaerobic energy system is influenced by numerous variables, including the neuromuscular system, mechanics, and buffering capacity. 
  • Therefore, relying solely on the model may neglect these other factors that impact performance.
  • Individual profiles across a performance continuum can vary greatly, and trying to fit every athlete into the same model may not be effective. Each athlete has unique characteristics and requirements. 
  • For example, a sprinter like Mark Cavendish in professional cycling may possess a significant power reserve, but this may not align directly with the estimations from the critical power model.
  • It is important to consider both the principles of critical power and the principles of speed reserve. 
  • Training programs should aim to develop capacities in both the aerobic and anaerobic energy systems, as detaining aerobically can increase the reliance on the anaerobic energy system.

The importance of speed reserve for a recreational marathoner

1:05:15 -

  • One crucial question to consider is how we can maintain speed, handle challenges during a race, and perform speed surges towards the end. 
  • Research from Finland on five and 10-km races has highlighted the importance of recruiting more fast-twitch muscle fibres to support performance as our slower-twitch, endurance-type fibres fatigue.
  • Training our ability to generate force and effectively utilise fast-twitch muscle fibres becomes crucial in these situations. Without this training, we may hit a performance ceiling quickly, as observed in tests conducted on marathon runners. While they may perform well in the threshold zone, they struggle to recruit faster fibres near their VO2 max.
  • To overcome this limitation, even endurance-dominant individuals need to focus on training the recruitment of fast-twitch muscle fibres and developing the ability to activate them rapidly. 
  • This training allows us to respond to surges and maintain speed when faced with fatigue.
  • It's important to clarify that we are not referring to hard anaerobic intervals but rather to exercises that emphasise maximal strength and low-level plyometrics. 
  • By focusing on foundational qualities such as quick activation, force production, reactive movements, and recruitment of fast-twitch muscle fibres, we can enhance our ability to adapt to changes in speed and optimise performance.

Top-Three Tips for Athletes to improve performance

1:07:24 -

  • Understand the speed and endurance balance within the group: It is crucial to assess athletes' individual strengths and weaknesses in terms of speed and endurance. 
  • By doing so, we can tailor their training programs to maximise their strengths and address their weaknesses effectively. 
  • Mismatching a speed-based athlete with an endurance-dominant program, for example, would not optimise their potential.
  • Train weaknesses based on individual profiles: While training all elements of the speed and endurance continuum is important, the approach to addressing weaknesses should be specific to each athlete's profile. 
  • Continuous training may become anaerobic for speed-based athletes who are more fast-twitch. 
  • Building fitness through shorter intervals and volume progression would be more appropriate in this case. 
  • Training stimulus selection should be aimed at maximising individual performance factors. 
  • Endurance-based athletes, for instance, benefit from high aerobic system utilisation during championships, focusing on maximising VO2 max, critical speed power, and endurance at critical power.
  • Designing training programs that align with each athlete's unique strengths, weaknesses, and performance goals is crucial. 
  • By tailoring training to individuals and understanding their specific needs, we can enhance training responses and increase the likelihood of achieving desired outcomes. 
  • While beginners can be exposed to various training elements, experienced athletes with a solid training background require a more personalised approach to maximise their potential and aim for podium success.

Rapid-Fire Questions

1:11:01 -
What's your favourite book or resource related to endurance sports?
I like listening to podcasts and spending time with people that taught a lot about these topics.

What's an important habit you've benefited from athletically, professionally or personally?
Being consistent.

Who's somebody that you look up to or that has inspired you?
I  have influences outside of sports—people like Ray Dalio, who are very first principles thinkers, have greatly influenced my practice. 


Bernardo Gonçalves

Bernardo is a Portuguese elite cyclist and co-founder of SpeedEdge Performance, a company focused on optimising cycling and triathlon performance. He writes the shownotes for That Triathlon Show, and also produces social media content for each new episode.

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