Competitive athletes undergo rigorous training schedules in effort to improve physical capacities and thus enhance sports performance. The acute response to intense physical training is a potent perturbation of homeostasis; characterised by a reduction in physical performance due, in part, to damaged muscle tissue, altered neuro-endocrine function, depleted glycogen stores, accumulation of metabolites and increased inflammation. This serves as a potent stimulus for adaptive mechanisms to heal and repair the body such that tolerance to a similar exercise stimulus is increased for future sessions as seen with the repeated bout effect.
These acute responses to training have primarily been studied following intense strength or endurance training. Much less is known about the acute effects of power training where loads are submaximal (typically <85%) and maximal intended velocity is expressed for usually <5 reps. Understanding how the body responds to both strength and power training can be useful for training program periodization.
A new study published ahead of print in the International Journal of Sports Physiology and Performance compared the acute effects of a power session and a strength session in 10 elite track and field athletes. On two separate occasions, the athletes performer either a strength or power workout consisting of 3 exercises. For the strength workout, athletes performed 4 sets of 5 reps for the barbell back squat, split-squats and push-press. For the power workout, athletes performed 4 sets of 5 reps for speed squats, split-squat jumps and power-press. Ratings of perceived exertion (RPE) were documented following each workout. Surface electromyography (EMG) of the thigh, barbell velocity and knee angle were measured during all exercises. Additionally, before immediately after and 24-hours after the workout, the researchers tested maximal voluntary contraction, jump height, central activation ratio and lactate.
The results showed that repetition duration, impulse and total work were greater during the strength workout than the power workout. Blood lactate levels were increased following strength sessions but not power. EMG showed increases across all sets for both workouts with strength sessions demonstrating greater activation at the end of the final set. Maximal voluntary contraction decreased following the strength session and remained suppressed at 24 hours while it remained unchanged following power training. RPE was higher for the strength session compared to the power session. Ultimately, this study showed that strength sessions take a higher toll on the body, and are likely to compromise performance 24 hours post-session. Coaches should therefore plan strength sessions with adequate recovery before subsequent sessions or competitions. In addition, power sessions may be preferable closer to competition or before practice sessions as this type of training will have less impact of fatigue and performance.
Reference:
Howatson, G., Brandon, R., & Hunter, A. M. (2015). The Response To, and Recovery From Maximum Strength and Power Training in Elite Track and Field Athletes. International Journal of Sports Physiology and Performance. In Press.
