Biomechanical Interventions

Matt Long, Jamie French, and Barry Cook explore how coaches can affect biomechanical adjustments in the running form of athletes.

This article assesses the extent to which coaches can make a series of short, medium, and long-term coaching interventions to attempt to effect biomechanical change amongst athletes by using a case study of the double Olympic and world champion Mo Farah. It is of primary importance for athletes, such as Mo, to practice a technically proficient and efficient skill to develop optimum performance. If a skill is poorly practised due to fatigue, that skill will be reinforced rather than the technically accurate skill.

We begin by exploring the work of US coaching guru, Alberto Salazar, and his creation of subtle biomechanical adjustments to his athletes, including Farah.

Biomechanical focus

According to Jennifer Kahn's The Perfect Stride (2010), Mo's coach Salazar, took a genuine interest in running form from 2006 onwards after being mesmerised by the style of a three-time Olympic champion, Ethiopia's Kenenisa Bekele. After consulting multi-Olympic gold medallist Michael Johnson and staff at his Performance Centre, who measured the angles of Bekele's arms and legs during his stride pattern. The realisation hit Salazar that the current world record holder for 5000m and 10,000m had an arm action that was not dissimilar to that of a sprinter. The rapid trail leg retraction effected by sprinters enabled their running to (a) generate more power and (b) give the foot a shorter distance to travel before it arrived ready to begin another stride - this allowed for an increase in cadence and ultimately speed.

Salazar who won three consecutive New York marathon titles in the1980s carried out his work within the Nike Oregon Project, which was created back in 2001 as a response to a perceived poor performance by American endurance athletes. Salazar began to experiment with top US distance runner, Dathan Ritzenhein who had finished ninth in the 2008 Beijing Olympic marathon and who parted with longstanding coach Brad Hudson in May 2009. Salazar noticed a range of biomechanical deficiencies with his newly acquired athlete and worked on effecting change with some of the following idiosyncrasies.

Heel striking

Video analysis showed that Ritzenhein was a heel striker over-striding with a resulting braking effect upon ground contact. This is caused by Newton's third law of motion that states: "For every action, there is an equal and opposite reaction." This means that if you over-stride and heel strike, every time you hit the ground, the reaction forces are backward and upwards, giving a braking effect instead of downwards and forwards. In analysing Bekele, Salazar observed that by drawing his lower leg down and backward, and slightly pulling the toe up a more neutral foot position, a positive acceleration could be achieved by minimising this braking effect and allowing for a much quicker transfer into the support and drive phase of the stride.

Foot placement

With the aid of Nike biomechanical expert Gordon Valiant, Salazar studied the loading patterns regarding the amount of force exerted on parts of the foot during impact. Salazar noted that Ritzenhein was placing his foot too far forward in front of his centre of mass, which was inefficient as the hamstring had to work hard to pull the body's trunk over the forefoot. By pulling the foot strike closer to underneath the centre of mass, Salazar realised this would also decrease the braking effect described above.

Hips

Ritzenhein's hips were relatively low compared to the 'high hips' of the 11-times senior world cross country champion Bekele which were carried directly under the body. Salazar became aware that high hips allow a longer stride length and force to be more directly transferred up through legs, hips, and upper body, affecting more excellent forward propulsion.

Elbow drive

In comparing Ritzenhein to the great Bekele, Salazar observed that the former had an elbow drive of approximately 60 degrees. In contrast, the latter could generate more force by driving his elbows back in the region of 70 degrees. The drive of the arms backwards balances the lower body forces, meaning that a greater, more forceful arm drive will balance more force produced by the legs.

Hands

The level of attention to detail that Salazar gave to Ritzenhein was meticulous and even stretched so far as to the athlete being challenged to drop his previously rigid upturned thumbs down and placed relaxingly on his index fingers.

Is it possible to affect biomechanical change?

Notably, the modification of Ritzenhein's style has not been without problems, and he has suffered injuries. Still, like Salazar himself acknowledged, "When you start changing an athlete's form, there's always a risk." Since switching to Salazar, Ritzenhein finished sixth in the Berlin world championship 10,000m in a personal best of 27min 22.28sec and became only the third American in history to break the 13-minute barrier for 5000m in that same year. He also took a world half marathon championship bronze medal in Birmingham (60:00) and set a marathon personal best of 2hr 07min 47sec in 2012. Despite leaving the Oregon Project in May of this year to move closer to home in Grand Rapids, Michigan, Ritzenhein continues to seek advice from Salazar.

The point of this piece is not to argue whether Alberto Salazar deserves to be ranked as an all-time great coach, as many would say that there are far greater exponents of the art of distance running than Ritzenhein. The thrust of our argument is that coaches can make evidence-based interventions to change the running style of their athletes to attempt to produce more economical, efficient, and effective performance over some time.

So what?

The arguments above leave both coach and athlete with many questions for self-reflection:

I need to challenge the conventional stereotype that sprinting and endurance running are two mutually exclusive athletic disciplines?
As a coach or athlete, do I pay enough attention to the technical aspects of running?
As an athlete, am I self-aware about the biomechanics that my body affects during training or competition?
As a coach am I cognizant of what I need to be looking at in terms of the biomechanics of my athlete(s)?

Now what?

The basic technical template for endurance offered as best practice by British Athletics is modelled on the following:

Tall posture with high hips
Relaxed shoulders with efficient backward driving arm action
Rhythm guides optimal speed and efficiency
The foot lands naturally underneath the centre of mass, moving down and backwards.

While this technical template tells you the outcome that we, as coaches and athletes, are aiming for, it does not tell us about the journey needed to get there. We continue our journey below.

Effecting specific biomechanical changes

Dr Jessica Leitch of Oxford University (2013) wrote in BMC News articulating some biomechanical observations which make Mo Farah run more efficiently. They focused on (1) gait cycle, (2) foot placement, (3) Arms and (4) Core.

Gait cycle

Farah has undoubtedly optimised his stride length under the guidance of Salazar in terms of his gait cycle. He no longer overstrides and has a trail leg action which quickly pulls his rear heel up to his buttock to prepare for the next stride. In recent years, he has increased his cadence too and is closer to optimum stride frequency, at which point the energy cost of running is the least (Grimshaw et al. 2007).

The Newham and Essex Beagles man has managed to increase the ratio of the 'swing' phase of his gait cycle (when the foot is in the air) compared to the 'support' or 'stance' phase (when the foot is on the ground). His action is far closer to that of a sprinter whose 'stance' time represents approximately one-fifth of the gait cycle when at maximal speed.

Foot placement

When the first contact point is in the rear third of the foot, an athlete is classified as a rearfoot or 'heel' striker. Those who make contact in the middle third of the foot are referred to as 'mid-foot', and those whose first point of contact is the forward third of the foot are classified as 'fore-foot' strikers. Farah is a mid-foot striker for the vast majority of his races, over 5000m and 10,000m, and in terms of foot placement, his foot lands slightly in front of his centre of gravity (COG). His foot stance time is at fractions of a second, which further decreases during his famed sprint finish over the final 400 metres. So how can both athlete and coach work towards the above?

Arms

The arms act as levers which in biomechanical terms are a series of connected rigid bars that rotate about an axis of rotation or fulcrum. As levers, the arms are important to the provision and application of force by initiating movement (on the start line) and continuous movement. Video analysis confirms that Mo holds his arms relatively high with a markedly bent elbow. Not only does the drive of his arms backwards balance his lower body forces, but it helps to effect greater forward propulsion. Mo's shoulders tend to remain relaxed, allowing the arms to move more freely and therefore assist in propelling him forwards. There is little movement where the arms across the chest, which prevents the body from rocking from side to side, as often occurs with runners experiencing fatigue. His hands tend to remain open with his relaxed thumbs placed on his index fingers.

Core

It is the ability of the transversus abdominis, both internal and external obliques, the quadratus lumborum, and the diaphragm to stabilise the core of the body during movement. This provides a stable platform for the limbs to move and exert force. While present at the Luzhniki Stadium for the 2013 world championships in Moscow, Long observed that Mo was able to keep a relatively level and stable pelvis even during the latter part of his 10,000m final. If the hips remain low, this tends to look like a sitting position, which restricts stride length and the amount of force generated by the drive leg pushing downward and backwards. Keeping his hips high allows for Mo's longer stride length to be maintained throughout his races aiding force to be more directly transferred up through his legs, hips and upper body, thus facilitating greater forward propulsion. Grimshaw et al. (2007) note that at foot strike, the hip is flexed to around 45 degrees and that during the drive-off phase, the hip extends to approximately 9% at toe-off. By maintaining a tall posture with high hips, the knee is prevented from collapsing inwards, leading to a more efficient application of force and helping Mo run faster.

Coaching interventions

It may be helpful if both athlete and coach think about potential biomechanical adjustments being made in the (a) short, (b) medium, and (c) long term. A short-term intervention may be something that the coach and athlete can affect during the session itself or shortly afterward. A medium-term intervention may involve modifications for weeks or even months in terms of a 'microcycle' or 'mesocycle' of training. A long-term intervention may include changes to the periodised training program of an athlete over many months or even years.

Short-term

This may be a command-based intervention shouted by the coach to the athlete during a training session. Galligan et al. (2000) refer to it as 'concurrent feedback'. In conducting previous research for the British Milers' Club, Long (2013) found that coaches made two fundamental types of trackside interventions, namely: (a) goal and (b) process-based. Goal-based interventions may be shouts of encouragement about where an athlete is placed in the race. In contrast, process-based interventions relate more to physiology and biomechanics, and therefore to make improvements in running form, it is the latter we are interested in here.

Some process-based interventions may, however, be more appropriate than others. For instance, how often have you have been trackside and heard coaches shout: "Lengthen your stride" or "Pick your knees up?" These are possibly two of the most common verbal interventions. Significantly, the former intervention is not appropriate because it appears to be about process, but it is still a goal-based intervention. A coach shouting "Lengthen your stride" says nothing about achieving this. On the other hand, at least the command "Pick your knees up" gives the athlete a clue about how to make a biomechanical adjustment, which may ultimately result in the goal of increased stride length.

Long regularly makes concurrent verbal interventions when coaching with national mentor Bud Baldaro and Sally Straw with the Birmingham University squad, which contains international athletes. One such intervention is the command to 'run as if you had a helium balloon attached to the top of your head'. This intervention ensures that athletes immediately maintain a tall posture with high hips. A second intervention often recommended is the command-based analogy to 'not spill the bucket of water. Getting the athlete to visualise a bucket of water seated inside the pelvis and a forward or backward tilting pelvis 'spilling' the water helps maintain a 'neutral pelvis'. The utilisation of the above encourages the coach to develop an understanding of neuro-linguistic programming in terms of an awareness of the learning preferences of diverse athletes. Using verbal interventions to invoke mental imagery will work best with athletes who favour both aural and visual learning rather than those who learn kinaesthetically or by reading and writing. (Fleming, 1995).

The danger of making verbal interventions is that (a) sometimes coaches are too quick to give feedback, rather than observing in silence to make sure what they are witnessing is ingrained running form, as opposed to a proverbial one-off and (b) the fact that athletes and people more generically do not tend to learn as much from didactic, instructional commands. This may, in turn, compromise long-term changes from occurring.

Medium-term

We know that in specific cases, if the front and rear leg range of motion are less than optimal, force is not applied in the correct direction. It then becomes necessary to slightly increase the range of motion, which could depend on hamstring and hip flexor flexibility or strength. A medium-term drill-based intervention would, for example, involve the coach and athlete incorporating static stretching into the training program as part of a discreet flexibility session. It is worth noting that the latest research indicates that static stretching is an inappropriate mode of warm-up, and stretching to restore range of movement (ROM) should take place after sessions (holding stretches for up to 15 seconds). To optimise stride length where a shortened stride is caused by an imbalance around the hips, the aforementioned longer stretches should be used over 25-30 seconds to extend ROM. As well as static stretching, both knee lift drills and eccentric squatting can also be used to improve flexibility while also training other biomotor abilities. A word of caution should be raised as excessive flexibility may compromise front and rear side running mechanics. This could lead to the foot hitting the ground too far in front of the body, which causes breaking, and excessive push-off behind the body, where little or no force is being applied.

The trail leg length of force production can be improved by quadriceps flexibility. Cadence is dependent on fast-twitch utilisation, which can be improved by plyometrics such as hopping, bounding, and double foot jumps. Explosive weights and plyometrics training help to increase the amount of force that can be generated quickly. More efficient foot striking can be improved with drills associated with dorsiflexion, which is the bending toward the extensor aspect of a limb. For example, hurdle drills pulling the trail leg over and pulling the toe up into the top of the trainer help. Additionally, static stretches of the gastrocnemius and soleus help. More effective foot placement can be aided by hamstring and glute strengthening plus hip flexor and hamstring curls. A reduction in foot stance time can be improved by plyometrics and sprint-based drills such as 'Flying 30s' (achieving a top speed in approach and maintaining speed over a 30m zone).

A medium-term intervention favoured by French in his coaching at Leeds Met University is to periodically get runners to hold crisps between their fingers and thumb so that they learn to maintain both relaxed hands and shoulders. In terms of working core stability, a dynamic plank whereby left and right legs are alternatively moved away from the core and side to side would be an appropriate drill to be performed over a Microcycle or mesocycle of training. Al, lateral side bends - weighted with a dumbbell - can be effective along with medicine ball work with forwards, backward and overhead movement needing to be used as well as the kind of lateral movement with the aforementioned side bends. The maintenance of a level pelvis is dependent upon hamstring and lower back flexibility as well as hip flexor strength, so both the lengthening and strengthening of muscle groups around the pelvis is paramount. Isometric squats can help to develop strength in this area which also aids foot placement. To prevent the inward collapsing of the foot at the point of ground contact, the gripping of a towel with one's toes to strengthen the foot arch is recommended.

Long-term

For a longer-term intervention, the appropriate use of downhill running for the athlete over months and years would be useful. Archer (2011) recommended that downhill running repetitions can be practiced on a preferably soft, smooth, flat, gradual grass hill of between 50 and 200 metres in length. Coaches and athletes can learn from Newham et al. (1988) research which guards against over-striding by keeping foot plants directly under the COG to 'glide' down the hill. A longer-term intervention like downhill running needs to be built into a periodised program that considers the frequency, intensity, and duration of sessions appropriate for long-term athlete development.

Mo Farah has undoubtedly progressively developed the fitness components of his training in terms of its frequency, intensity, and duration over the years. This leads to the athlete being able to more correctly model best practice in technical terms because the onset of fatigue will be delayed. Ericsson (1990) said that 10,000 hours of practice is needed to reinforce the skill. Having said this, if a skill is practiced badly due to fatigue, that badly practiced skill will be reinforced, rather than the technically proficient and efficient skill needed for optimum performance.

Conclusions - Now what?

Through a case study of the work of Alberto Salazar with Mo Farah, we have argued that it is indeed possible for coaches to make a range of short, medium, and long-term interventions to effect biomechanical change amongst athletes. To inform your coaching practice, consider using the following set of self-reflection to guide your future focus on biomechanics:

Do I, or does my athlete need to think about incorporating interventions into a systematic training program to make biomechanical adjustments to run more efficiently?
Am I or is my athlete prepared to make appropriate interventions to make biomechanical adjustments in the short, medium, and long term?
Am I or is my athlete aware of best practices in modelling efficient biomechanics? This may include using the British Athletics uCoach website and event-specific templates.
Am I or is my athlete prepared to be aware that making biomechanical adjustments can lead to unintended negative consequences in terms of performance and injury if affected inappropriately?
How am I, or my athlete, going to monitor and evaluate whether the biomechanical adjustments made are impacting the desired outcome in terms of enhanced performance?

Article Reference

The information on this page is adapted from a series of three articles that appeared in Athletics Weekly between 10^th and 24^th July 2014 with the kind permission of the authors and Athletics Weekly.

Page Reference

If you quote information from this page in your work, then the reference for this page is:

LONG, M. FRENCH, J. and COOK, B. (2015) Biomechanical Interventions [WWW] Available from: https://www.brianmac.co.uk/articles/article192.htm [Accessed

About the Authors

Dr Matt Long, Barry Cook, and Jamie French are Coach Education Tutors with British Athletics.