Title: ALTERATIONS IN COUNTERMOVMENT JUMP PERFORMANCE FOLLOWING COMPLETION OF A MOUNTAINOUS ULTRAMARATHON
Thesis Supervisor: Dr. Darren Warburton
Committee members: Dr. Andrew Perrotta, Dr. Michael Koehle
Defence Chair: Dr. Bill Sheel
Abstract:
BACKGROUND: Ultramarathons lie on the extreme end of endurance sport duration. With ultramarathon participation increasing in recent years, there is a need for more research on factors that influence ultramarathon performance, and the potential effects of completing an ultramarathon on the musculoskeletal and neuromuscular systems. This study investigated countermovement jump mechanics in ultramarathon runners and identified potential changes after running a race. METHODS: Twenty-one runners (6 female, 15 male) were recruited from the FatDog 120 Trail Race, an ultramarathon trail race in British Columbia, Canada. Runners were examined before and after ultra-endurance mountain races of 64km, 80km, 112km, and 192km. Height, weight, percentage body fat were collected, and the participants performed 5 jumps on a portable force plate system (Hawkin Dynamics, USA) to assess jump height, as well as related force-time variables in the braking and propulsive phases of the jump. Paired T-Tests were conducted for statistical analysis to assess changes from pre- to post. Pearson Product Correlations were determined for variables and relative finishing time. RESULTS: Significant decreases were observed in jump height (-33.6% ± 17%), average relative net braking impulse (-33.1% ± 19%), braking rate of force development (-60.1% ± 25%), and propulsive net impulse (-19.3% ± 11%). Significant increases were observed in braking phase time (52.7% ± 55%), and propulsive phase time (8.85% ± 16%). No countermovement jump variables displayed any significant correlation to relative finishing time, however, body weight (r = 0.49), and BMI (r = 0.52), were significant. CONCLUSION: Ultramarathons result in altered jump timing, limiting force application, and impact the ability to use elastic energy. Ultrarunners may benefit from downhill training or strength training to improve these characteristics.