The warm-up protocol used before training and competition is often taken for granted and the time allotted may not be used optimally by coaches. Increasing body temperature and ensuring that various movements are performed in each plane and through a full-range of motion is important for reducing the risk of injury. However, typical activities performed during the warm-up such as jogging, side-shuffling and dynamic stretches may not cut it for optimizing performance potential. Coaches who are familiar with post-activation potentiation are aware that force production and rate of force development can be enhanced with certain exercises. Therefore, strategically implementing potentiating movements in the warm-up may lead to subsequent enhanced performance of explosive actions like sprinting and jumping. However, timing likely plays an important role in the effectiveness of such a strategy as waiting too long may result in loss of potentiation effects.
A new study published ahead of print in the Journal of Strength and Conditioning Research aimed to determine the potentiating effects of drop-jumps incorporated into the warm-up routine on the time-course of changes in lower body strength and power. A group of 20 collegiate athletes performed both an experimental warm-up that included 2 sets of 5 drop jumps (15 s between repetitions and 3 min between sets) and a control warm-up (walking). The protocol order was randomized and separated by at least 72 hours. To evaluate whether the experimental condition impacted lower body performance potential, electrically-evoked isometric muscle twitches were recorded throughout each protocol to measure peak twitch torque, rate of force development, amplitude and impulse.
The results showed that the warm-up protocol involving drop-jumps significantly increased peak twitch torque (23%), rate of force development (39%) and impulse (46%) while these parameters were significantly reduced following the control protocol. Interestingly, there was no change observed in amplitude which the researchers interpreted as evidence that that augmented torque was due to post-activation potentiation. Regarding the time-course factor, the researchers found that the potentiation effects returned to baseline within 6 minutes of the drop-jumps and trended below baseline within 15 minutes. Thus, it was concluded that drop-jumps acutely enhance muscle force generating capacity and that they should be implemented immediately before competition to take advantage.
Johnson, M., Baudin, J. P., Ley, A. L., & Collins, D. F. (2017). A warm-up routine that incorporates a plyometric protocol potentiates the force generating capacity of the quadriceps muscles. The Journal of Strength & Conditioning Research.