Interval Training – Can We Do Too Much?

Interval training, in the form of repeated sprints, is a common modality used in training programs for those in team sports.

You certainly can’t discount the fact that these athletes need more than the long-slow aerobic type of training that was more common years ago.  Most team sports are intermittent in nature, so various forms of interval training lend themselves well to preparing the athletes to do work at a high or relatively high intensity, recover quickly (sometimes in a minute or less) and then perform a high amount of work again.

There is certainly enough research over the past few years to support this contention.  Here is a brief synopsis of two articles on the subject of interval training and team sport athletes:

  • Continuous training (aerobic work for 20-25min) was compared with Interval Training (10sets x 10sec max pedaling on a bicycle ergometer followed by 20sec of recovery) in Eighteen lacrosse athletes.  Vo2max increased significantly in both groups during the aerobic exercise test (incremental cycling test to exhaustion), while maximal anaerobic power only increased significantly in the interval-training group.  Additionally, the interval-training group saw improvements in maximal power in both the early and late stages of the intermittent exercise test (10sets x 10sec max bike sprint followed by 40sec rest).  The researchers concluded that, “Ball game players should therefore improve their endurance capacity with high-intensity intermittent exercise, and it is insufficient to assess their capacity with only Vo2max or continuous exercise.”
  • Female college hockey players participated in a study evaluating the relationship between aerobic capacity – measured by Vo2max – and recovery from high intensity intermittent exercise.  The athletes were asked to skate 5-one lap intervals around the rink, separated by 30-seconds of recovery.  The researchers found that aerobic capacity was not significantly related to the ability to recover from high intensity exercise.  Thus, they concluded that, “Coaches and trainers probably do not need to include aerobic training in their practices, because high intensity interval training commonly seen in hockey training also improves aerobic capacity, as reflected in the Vo2max values of these subjects.”

Over Doing It?

As they say, “To much of a good thing can become a bad thing.”

I have gotten the impression that with all the research about interval training and sports preparation, some may be overdoing it, as it is not uncommon to see people programming intense interval workouts daily or several times a week (oftentimes in addition to the athletes regular sports practice).

It is important to remember that interval training can place a high amount of fatigue on the body.  If an athlete is not recovering from this type of training, there is a potential for overtraining.

One particular study looked at the muscle damage following a bout of sport specific repeated sprints.  The subjects performed 15 x 30m sprints with a 10m deceleration zone.  The deceleration zone was used as way to simulate sports specific activities, since team sports often require change of direction, cutting and high amounts of deceleration.  This is also the reason many coaches favor shuttle runs as a means of interval training, as it simulates the dynamic environment during game situations.  Each repetition in the study was followed by 60-seconds of rest.  The researchers measured maximum isometric force (MVC), serum creating kinase activity, muscle soreness (DOMS) and limb girth before training and at 24-hours, 48-hours and 72-hours after exercise.

Creatine Kinase and DOMS were elevated above baseline for 72-hours post training, while maximum voluntary contraction showed a decline at 24 and 48-hours post training, and limb girth was elevated for 48-hours post training.

These results led the researchers to conclude that, “These data show that the repeated sprint protocol with a rapid deceleration precipitates significant levels of damage in the days following the exercise bout and therefore may be used as a suitable alternative to examine the damage response from a sport specific repeated sprint mode of exercise.”

Conclusions

Much like resistance training, you can’t go heavy everyday or  all the time.  Your body needs a break and either you give it the break it needs (proper programming) or it forces you to take that break (injury).

Interval training is a very specific modality that has many applications.  Obviously, identifying the intensity of the intervals is important.  This is one of the reasons why I advocate grading the intensity of the training as “High/Medium/Low”.

Two high days in a row will certainly be pushing the envelope (not that it can’t be done) and would certainly warrant a low day or off day at the completion of those two training days.

Typically I am a fan of sequencing between days of high intensity work and days of low intensity work.

High intensity work would be things like heavy lifting (especially lower body lifts), olympic lifting, intense plyometrics, interval work, sprinting, etc.

Low intensity days would be things like body weight circuits, low intensity medicine ball circuits, tempo runs, etc.

Medium days would fall somewhere in the middle where the intensity is moderate or moderate to high and/or the volume is low.

One thing about the tempo work is that you need to be objective with yourself and perform within the appropriate intensity.  I believe Charlie Francis said something like, “Most people’s tempo work is to high of an intensity to be considered tempo work and to low of an intensity to be considered speed work.”  Basically, we are working harder than we should, instead of backing off the intensity during the tempo work and allowing ourselves to develop an appropriate work capacity and recover adequately so that our high intensity days will not be compromised.

In the article Cardio: Intervals, Tempo Work and Steady State I get more into making the distinctions between these types of things, as well as give some practical application of these training modalities.

In a nutshell, understand the training objectives and modalities you choose to prescribe to your clients/athletes.  There is nothing wrong with backing off the intensity and allowing the body to recover, as the body can only adapt to so much stress at one time.

References

Tanisho K, Hirakawa K. Training Effects of Endurance Capacity In Maximal Intermittent Exercise: Comparison Between Continuous and Interval Training. J Strength Cond Res2009;23(8):2405-2410.

Carey DG, Drake MM, Pliego GJ, Raymond RL. Do Hockey Players Need Aerobic Fitness? Relation Between Vo2max and Fatigue During High-Intensity Intermittent Ice Skating. J Strength Cond Res 2007;21(3):963-966.

Howatson G, Milak A. Exercise-Induced Muscle Damage Following a Bout of Sport Specific Repeated Sprints. J Strength Cond Res 2009;23(8):2419-2424.