Recently I have been running a few seminars on “How To Run Faster”. My main client base for these have been Crossfit gyms. Initially, I didn’t think that being able to run quicker would be useful for Crossfit athletes. However, having spoken to the athletes and coaches it became apparent that it was indeed something that could improve their performance. The reasons for this are that sprint training facilitates positive training adaptations and are, therefore, a useful training modality. Many people doing Crossfit also take part in other sports, and so getting the knowledge to improve their speed could also be useful to them.
I guess the first place to start is to discuss why speed training may be useful for athletes involved in Crossfit. For those of you that don’t know, Crossfit is essentially the sport of exercising (and has come in for a lot of criticism because of this!). A Crossfit competition can last between one and four days, and consists of a number of different workouts aimed to stress different aspects of fitness. Good all round athletes tend to perform better than specialists. To illustrate this, the events at the most recent Crossfit Games included:
- The Beach – a workout involving swimming, kettlebell thrusters, and burpees
- 1 Rep Max Overhead Squat
- Triple 3 – 3000m Row, Skipping, and 3 mile run
- Sled push for time
- Squat Clean ladder up to 345Ibs (157kg)
So you can see that, to be successful, an athlete has to be strong, but also have good endurance capacity. Successful athletes also need to have good strength outputs over a prolonged 5-10 minute period because many workouts last this length of time.
Although having to sprint in Crossfit is pretty rare, doing so in training can be useful. One type of adaptation to sprint training involves the enzymes involved in energy production. Multiple bouts of sprint training allow us to increase the speed at which we replenish our ATP-PC stores. Some studies have shown that repeated bouts of sprint training increase muscular levels of CPK, which is an enzyme that catalyzes the breakdown of phosphocreatine. Other enzymes, such as phosphofructokinase, which are involved in anaerobic glycolysis, also increase as a response to sprint training. This leads to the ability to be slightly more efficient at a given velocity, and could well improve anaerobic metabolism in Crossfit athletes. Both long duration and short recovery sprints can cause adaptations to the aerobic system. A study by Dawson et. al. showed that maximal oxygen uptake (VO2 max) improved after short sprint training. As Crossfit is comprised of events requiring a decent aerobic capacity, these improvements would certainly be beneficial. An additional factor is that by improving VO2 max, athletes might be able to recover between events slightly quicker, which becomes very important in a prolonged competition such as the Crossfit Games.
A further adaptation to sprint training is that it improves the intramuscular buffering capacity, particularity if the sprints are of longer (roughly 30 second) duration. This improved buffering will enable a better resistance to fatigue in high-intensity events, such as the typical high intensity Crossfit WOD.
Perhaps of even more interest to Crossfitters are the muscle adaptations to sprint training. Long term sprint based training increases the proportion of type II (fast twitch) muscle fibers an individual will have. The evidence is less clear on whether these improvements are in type IIa, IIb, IIx, or any of the other proposed type II fiber types. Nevertheless, an improvement in type II fibers will enable the athlete to produce more force, which would be useful in the strength based exercises demanded by competitive Crossfit events. Long-term sprint training has also been shown to induce muscle hypertrophy, which again is a useful adaptation for a Crossfit athlete. Finally, sprint training improves the muscle conduction velocity, which means the motor units can fire quicker. Sprint training increases motor unit recruitment, which allows for a greater force production and may improve Olympic lifting performance.
As an additional point, sprint training also likely elicits an anabolic hormone response. An increase in circulating human growth hormone and free testosterone could lead to further improvements in lean body mass and body composition that would be favorable for competitive Crossfit athletes.
Finally, sprint training can improve both posture and (potentially) endurance running performance. My previous article on whether or not endurance athletes should do sprint training discusses this in a bit more detail.
From the above, we can see that by using regular sprint training in their programs, Crossfit athletes could improve their performance through a variety of mechanisms.
How to Program Sprint Training
Crossfit involves workouts that are very intense, and they can be highly fatiguing, especially if they involve Olympic lifting. As such, within a typical Crossfit program, planning sprint training at an appropriate time point can be challenging. With sprint training, it is important to remember that it is a very central nervous system (CNS) intense activity. Sprinting at near to maximum capacity, whilst not always fatiguing in the energy system sense, will fatigue the CNS. Generally, the body requires about 48 hours of recovery from a sprint session. Activities of similar intensity to sprinting, such as plyometrics or Olympic lifting, or indeed another sprint session, shouldn’t take place until then. The danger of attempting a sprint session in a fatigued state is that you increase the risk of injury. You also will not have as high-quality session as if you were reasonably fresh, and so the training process becomes less efficient and effective. Finally, doing a sprint session in a fatigued state will deepen your fatigue, reducing the quality of subsequent sessions and increasing the amount of recovery you will need.
All this information can cause a bit of an issue; when should a coach program a sprint session for a Crossfit athlete? This obviously depends on the goals of each athlete, but as a starting point, most Crossfitters will not require more than two sprint sessions per week, and in fact one could well be sufficient. In this case, programming the sprint session as the first training session in each week’s training block would be ideal. The athlete will be fresh, and subsequent sessions can be done under fatigue to mimic the demands of a Crossfit competition. If two sessions were to be programmed per week, things would become a little bit trickier. It would still be a good idea to keep a sprint session as the first session of the training block – the question is where to place the subsequent one? Again, this depends on your program. If you have two rest days per week, then simply have the sprint sessions follow them – you will be well recovered from your rest days and have a high-quality session. If you don’t have two rest days, a sprint session could follow an easier day. For example, if you have an easier day programmed in which you do a lot of zone 1 / low heart rate aerobic work, then sprint training could quite comfortably follow this. Even a slightly more intense workout, which doesn’t involve lifting high loads, would be fine to precede a sprint workout. The sessions to avoid the day prior to sprinting are those that include high volumes of plyometrics and Olympic lifting, which will fatigue the CNS significantly.
Sprint workouts are useful as they induce fatigue. Ask anyone who has run a session involving multiple 200m sprints how they feel a few hours later, and they will describe a high level of fatigue. After running 5x200m on a Thursday morning in my University training group, I used just to go home and sleep for a few hours! This level of fatigue that is induced by sprint training can be useful to Crossfit coaches as it allows them to replicate the demands of competition on their athletes. Crossfit requires exercises to be done correctly under fatigue, and so finding an efficient way to mimic this fatigue is useful. Coaches should take care to ensure that proceeding workouts don’t stress the CNS to a significantly high level, as injury may occur – however, energy system intense sessions should be fine.
Measuring Sprint Training
Like every training aspect, improvements in sprint ability should be monitored and measured. This allows the coach to evaluate whether or not the training program is working as desired, and make any required changes. The validity and reliability of certain testing methods is beyond the scope of this article; however, one particularly valid approach is to time athletes over a certain distance. Timing workouts can be useful as it can act as a motivation to athletes to perform well. Speaking from experience, the days that my coach got the timing gates out were the days that I knew I really had to up my game. Recording times is easy, and gives very quick feedback; an athlete is either faster or slower. It’s also very repeatable, so long as the timing system used is reliable. To this end, hand timing by an inexperienced coach is probably not reliable enough, and so an electronic timing system should be used. These systems are now cheap enough and sufficiently portable to have a place in any training program.
Overall, it should be apparent that sprint training can be useful to Crossfit athletes and coaches, through a variety of mechanisms. One of the main issues is the adequate programming of sprint sessions within a training program; care should be taken to ensure sufficient recovery. Finally, electronic timing can be a quick and reliable way to both monitor training improvements and motivate athletes to perform at a high level.
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Dawson, B.; Fitzsimmons, M.; Green, S. et al (1998). Changes in performance, muscle metabolites, enzymes and fibre types after short sprint training. Eur J Appl Physiol 78 163-169
Ross, A. & Leveritt, M. (2001). Long-term metabolic and skeletal muscle adaptations to short sprint training: Implications for training and tapering. Sports Med 31(15) 1063-1082
Wahl, P. (2013). Hormonal and metabolic responses to high intensity interval training. J Sports Med Doping Studies 3(1)