Recent epidemiological data on U.S. cheerleaders suggest that injuries are on the rise and the majority of injuries sustained are strains/sprains of the lower extremities. The purpose of this study was to investigate possible neuromuscular factors contributing to injury rates in collegiate-level cheerleaders. Six female collegiate cheerleaders volunteered for this study. Participants underwent isokinetic muscular strength assessment of the knee flexors and extensors using an Isokinetic Dynamometer. The tests show that cheerleaders should increase their focus on conditioning and strength-training of the lower extremities to help avoid thigh- and knee-related injuries.

Cheerleading has become an extremely competitive sport over the last decade. Recent epidemiological data on U.S. cheerleaders suggest the majority of injuries sustained during cheerleading were strains/sprains of the lower extremities. Muscular weakness/ imbalances have been proposed as potential factors related to these types of injuries. PURPOSE: To investigate and identify possible neuromuscular factors contributing to injury rates in collegiate-level cheerleaders. METHODS: Six female collegiate cheerleaders (mean ± SD, age: 19.2 ± 1.3 yrs, height: 1.61± 0.07 m, weight: 56.3 ± 3.9 kg) who were members of the Nationals competition team for their university volunteered for this study. Participants underwent concentric isokinetic muscular strength assessment using the Biodex Isokinetic Dynamometer. The motor axis of the dynamometer was visually aligned with the axis of the knee joint of first the stabilizing leg (right) and then the stunt leg (left). The knee joint was adjusted so the leg was fully extended (knee angle = 0 degrees) to avoid hyperextension of the joint. After a standardized warm-up consisting of five submaximal concentric muscle actions, the quadriceps and hamstring muscles were tested at a velocity of 60°·s-1 for peak torque and subsequent analysis of the hamstrings-to-quadriceps (H:Q) ratio. RESULTS: No differences in quadriceps (p=0.371) (right leg: 111.1 ± 28.2 N·m, left leg: 105.5 ± 35.8 N·m) or hamstrings (p=0.098) (right: 62.2 ± 14.2 N·m, left: 56.4 ± 15.2 N·m) peak torque were observed between legs. The H:Q ratios were 0.54 ± 0.07 and 0.53 ± 0.04 for right and left legs, respectively. CONCLUSION: Although the current findings did not demonstrate any significant contralateral strength imbalances between legs, the results did reveal H:Q ratios below the proposed normative value of 0.6. Thus, cheerleaders should increase their focus on conditioning and strength-training of the lower extremities to help avoid thigh- and knee-related injuries.