The Benefits of Sprint Training

I'm sure by now you've probably heard of the many benefits of high intensity interval training or HIIT. This method of training involves performing an exercise or movement at near maximum intensity or effort for a short period of time, followed by a short rest, and repeating this pattern for an allotted time.

One benefit of this style of training is the amount of time you can save by shortening the length of time you need to spend exercising. One study has shown that when compared to weightlifting, and low intensity running and cycling, HIIT burns on average 33-43% more calories in the same amount of time (1). This means you could theoretically train for much shorter periods to achieve the same results in terms of calories burned.

One of the best forms of interval training is sprinting. Simple to understand, and easy to perform (though perfecting your technique for maximum efficiency takes time), it's one of the best methods of training that you can add into your own program and has many benefits over HIIT and lower intensity endurance training.

Sprinting Helps to Build Lean Muscle Mass

While sprinting may not increase muscle mass to the same level as strength and resistance training, it can be a huge compliment to your training to speed up your increases in muscle mass. Sprint training has been shown to increase the number and efficiency of fast-twitch muscle fibres in the muscles recruited in the activity (2). Type II or fast-twitch fibres are responsible for explosive and power based movements and are predominantly recruited when performing weighted resistance exercises. They contract quickly but also fatigue quickly hence why they are predominantly recruited when performing quick explosive movements for short periods of time such as jumping, weight lifting and sprinting. On the other hand, Type I or slow twitch fibres are responsible for endurance based exercises such as walking and jogging. They have a slow contractile speed but also take much longer to fatigue and are therefore recruited during longer and slower bouts of movement or exercise.

The reason Type II fibres are so useful when it comes to building muscle mass is that they have a much larger cross-sectional area than Type I fibres. This means a greater number of Type II fibres gained from training explosive exercises such as weightlifting or sprinting can result in more muscle mass in the recruited muscles.

• Something to Consider

While sprint training has been shown to increase muscle mass and power output, it lacks one fundamental aspect of continuous muscle growth that can be achieved through weight training. Progressive overload. Progressive overload is the gradual increase in stimulus the body needs to continue to improve. It involves increasing the weight, intensity, volume, time or frequency of training in order to force the body to adapt and become bigger, faster, stronger or more resilient. Without this constant increase the body will become used to the demands imposed upon it during exercise and will have no reason to develop or improve.

Progressive overload, in theory, is easy to achieve through strength training. One method is to increase the amount of weight lifted during a certain exercise as the current weight becomes easier and more manageable after a few weeks of training with that weight. With sprinting it is a little more difficult. The legs will only be able to move so fast and produce so much power and eventually you will see diminishing returns. One way to counteract this is to add some resistance into your sprint training by using a sprint parachute.

Sprint parachutes work by providing wind resistance and drag to force your legs to work harder to drive you forward. The best part is the faster you run, the more wind resistance there is and the harder you have to work! This goes some way to help increase the intensity of your sprint training which can produce greater returns in terms of increased muscular development.

Sprinting Increases Your Metabolism

With an increase in muscle mass comes an increase in metabolic rate. Bigger and stronger muscles require more energy to sustain and move, thus causing your body to burn calories at a faster rate to meet the demands of those bigger muscles, even while resting. This is a permanent (as long as the level of muscle mass is retained) effect and is one of the reasons why strength training is so important when trying to lose body fat and build a lean physique. But this isn't the only way sprinting helps to boost your metabolism.

When we move, our body produces a compound called adenosine triphosphate (ATP), the fuel our body uses for muscular contraction. This can be done through a mix of 3 different energy systems depending on the intensity of the movement. Phosphocreatine and glycosis (anaerobic), and oxidation (aerobic). The anaerobic systems are used for higher intensity exercises or movements lasting anywhere between a few seconds to a couple of minutes and do not require oxygen. The aerobic system is used for lower intensity exercise ranging from a few minutes to a few hours and uses oxygen to produce ATP and supply energy to the working muscles. During a sprint training workout our bodies will swap between these energy systems depending on current intensity, with the fast explosive sprints being supplied anaerobically and periods of rest and recovery being supplied aerobically.

So how does this relate to our metabolism? On average, for every litre of oxygen consumed we burn around 5 calories. Therefore, more oxygen consumed = more calories burned. So low intensity exercises, which rely on aerobic (oxidative) energy will burn more calories during that workout. However, high intensity training has been shown to increase something called Excess Post-Exercise Oxygen Consumption, or EPOC, significantly more than less intense levels of training (3). EPOC is our body 'catching up' and returning to a normal resting state (homeostasis) post exercise. Following a workout your body uses oxygen to restore muscle glycogen and rebuild muscle proteins damaged during exercise. Even after a HIIT workout is over, the body will continue to use the aerobic energy system to replace the ATP used during the workout, thus enhancing the EPOC effect. This increase in oxygen consumption can result in an increased metabolic rate for up to 38 hours after a workout has ended (4).

Faster metabolism = more calories burned!

Sprint Training Burns Fat

One of the most important aspects when it comes to losing body fat is maintaining a calorie deficit. This means the amount of calories we put into our bodies through our diet and nutrition is less than the calories we burn through exercise and our body's natural resting state. In short, energy consumption must be less than energy expenditure. With this in mind, the best exercises to perform to aid in this calorie deficit are exercises that either burn a lot of calories at the time, or increase our body's natural resting energy expenditure (base metabolic rate or BMR). Sprinting does both.

As discussed above, any form of explosive movement which recruits a large number of Type II muscle fibres has been shown to produce increases in muscle mass, and as we know, this is great for raising our metabolic rate. But studies also suggest that HIIT produces greater results in terms of body fat reduction than slower, steady state exercise: "When corrected for the energy cost of training, the decrease in the sum of six subcutaneous skinfolds induced by the HIIT program was ninefold greater than by the [endurance training] program" (5). This is great news if you want to save time during your workouts. A good quality sprint training workout can consist of just ten 30 second sprint intervals followed by 30 second recovery periods. That's just 10 minutes of training and only 5 minutes of actual work. Just be sure to make those sprints count and try to run at around 70-90% of your maximum running speed for the best results.

Watch this space for a full sprint workout coming soon, including warm up and cool down, and drills to help improve speed and explosive power to increase the efficiency of your workout.