The effectiveness of a passive warm-up protocol for musical theatre performance / Karen Palmer (2022)

It is widely recognised that warming-up prior to physical exercise is necessary for achieving optimal performance. There are several factors considered fundamental in a welldesigned warm-up, but primarily it should increase muscle temperature in order to stimulate metabolic responses in the body. Two types of warm-up are considered most prevalent, active warm-up (AWU) which consists of low and high intensity exercise and passive warmup (PWU) which increases Tm and Tc through external heating methods. It has been suggested that an AWU that is too intense may lead to fatigue, whereas a PWU achieves Tm elevation without depleting energy substrates. With this in mind, it was the primary aim of this research to determine whether an external heat source has value as a tool for a warmup in the dance industry where an AWU is not possible. Eleven non-professional dancers age 18+ with no injuries attended three sessions in which a countermovement jump (CMJ) was randomly preceded by a PWU, AWU or no warm-up (NWU) condition. The PWU condition produced the greatest muscle temperature increase and remained higher than the AWU following the transition period. Using 3D motion capture no significant differences were found in jump height (p =.148) and peak angular velocity of the ankle (p =.842) knee (p =.913) and hip (p =.761). No significant differences were found in landing phase joint angle of the ankle (p = .475), knee (p =.078) and hip (p =.122). However, significant differences in the knee angle were found between the PWU and AWU knee landing angle (p =.031). Force plates found no significant different in peak ground reaction force (GRF) during the take-off phase (p = .307) and peak GRF in the landing phase (p =. 307). However, a 28.4kg difference was found between PWU and NWU landing ground reaction force. Rate of force development showed a significant difference between PWU and NWU conditions (p =.008) and AWU and NWU conditions (p =.038). sEMG showed no significant differences in amplitude analysis. Findings suggest that a PWU has an equal benefit to dancers in terms of landing mechanics as an AWU. Which could lead to the use of passive heat as an injury prevention tool. This study has also provided evidence to show that a PWU is statistically almost as valuable as an AWU and noticably more beneficial than NWU across tests used. Suggesting that if a dancer is unable to actively warm-up then passively warming up would provide them many of the same benefits.