Multiple Sprints

The Autonomic Nervous System and Repeated Sprints

Published at September 15, 2007 in ANS and Multiple Sprints. 0 Comments

The autonomic nervous system or ANS is made up of sympathetic and parasympathetic nerves. The sympathetic nerves speed up various physiological processes such as heart rate and the parasympathetic nervous system slows down physiological processes.

It is possible to measure sympathetic and parasympathetic responses to exercise using heart rate variability. Heart rate variability is the time interval between heart beats and is usually measured in ms.

Scientists use heart rate variability information to study what happens to the ANS during and after exercise.

One particular interesting study is that of Buchheit et al. (2007) . These researchers studied a phenomenon known as parasympathetic reactivation.  

When we are at rest the parasympathetic nervous system is the predominant system we use to control normal bodily functions. However, when we exercise the sympathetic nervous system increases its activity and reduces the effect of the parasympathetic nervous system.

So, parasympathetic reactivation is the study of how long the parasympathetic nervous system takes to recover from exercise and return to baseline or near baseline measures.

What Buchheit et al. (2007) looked at was which type of training affected parasympathetic reactivation the most. The type of training looked at was repeated all-out sprints, continuous running or an intermittent exercise session.

The results showed that the activities that placed the highest demand on the anaerobic energy system ie. repeated sprints had the slowest parasympathetic reactivation.

This study really backs up what coaches have thought for a while, that anaerobic exercise places a considerable demand on the human nervous system.

What’s important is that we recognise that it’s not just muscles that need to recover from exercise but the nervous system too. This means we need to take into account rest periods during exercise and throughout training cycles in order to optimise training adaptations.

This point is especially valid when we are competing in sprint and intermittent type activities.

Alan Ruddock CSCS, YCS

Can endurance training aid multiple sprint performance?

Published at September 10, 2007 in Multiple Sprints and Soccer. 0 Comments

What are multiple sprints? Well, in team games players are required to sprint intermittently throughout the match and thus multiple times.

It is often the team who can compete at a high intensity for the longest period of time that wins the game. Specifically, the team that performs more high intensity sprints.

There are two key components required to be successful in multiple sprints. Firstly, the ability to run fast and secondly the ability to recover from high intensity sprints.

Sprinting places a considerable demand upon anaerobic energy systems and due to this many bi-products of energy production are formed.

Unfortunately for us, some of these bi-products slow us down by inhibiting various physiological processes.

It is therefore imperative that we reduce the impact of these bi-products by eliminating them from our body.

How? Through the magic of oxygen! Research has shown that when oxygen availability is increased multiple sprint performance also increases. In contrast, when oxygen availability is decreased the rate of muscle fatigue increases.

So how can we increase oxygen availability? EPO? Blood doping? Hyperbaric chambers? No. There’s a much more ethical and practical way. Endurance training.

An excellent example of how endurance training can increase multiple sprint performance is the research of Helgerud et al. (2001).

Helgerud et al. (2001) had elite junior soccer players running 4 intervals of 4-mins at 90-95% max heart rate interspersed with 3-mins rest twice per week for 8 weeks.

By the end of the training programme the players had increased the number of sprints they performed in a match on average by 100%!

Whether this performance increase was due to increased oxygen availability or other mechanisms is unknown, but what we do know is that endurance training facilitated this improvement.

My advice is that if you compete in an intermittent sport then you should always have an aerobic base, and training like the players in the study above will help you achieve an excellent base for the season.

Alan Ruddock CSCS, YCS