Abstract
The vertical jump (VJ), the gold standard for assessing leg power, is most commonly performed from a squat stance (SS). However, dancers often initiate jumps/leaps from a plié, externally rotated from the hip or "turned out" (TO). Testing dancers from a SS may not indicate activity specific power. This study's purpose was to determine differences in jump height and leg explosiveness, as measured by reactive strength index-modified (RSI-mod) when performed from TO and SS positions in dancers and non-dancers. Thus far, five healthy participants who are physically active at least ten hours/week have been studied; three dancers, having at least four years of ballet training (19.3±2.1 yrs, 66.7±11.7 kg, 1.70±0.05 m), and two non-dancers (24.5±3.5 yrs, 71.0±2.5 kg, 1.70±0.03 m). Post warm-up, participants performed three jumps from both TO and SS conditions. Time to take-off was determined as the time difference between the beginning of the eccentric lowering phase and take-off. Jump height was measured with a Vertec. RSI-mod was higher for TO than SS for dancers (0.70±0.18 vs 0.64±0.23), and similar for SS vs. TO for non-dancers (0.41±0.11 vs. .40±0.08). Dancers appear to have greater leg power overall than non-dancers, and generate more power in the TO vs. SS condition as indicated by higher jump heights and RSI-mod. Testing dancers from a TO position improves VJ performance.
Faculty Sponsors
Dr. Monique Mokha
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-7-2017 12:00 AM
End Date
4-7-2017 12:00 AM
Differences in Jump Height and Reactice Strength Index-Modified in Dancers and Non-dancers Performing the Vertical Jump from Two Positions
Alvin Sherman Library
The vertical jump (VJ), the gold standard for assessing leg power, is most commonly performed from a squat stance (SS). However, dancers often initiate jumps/leaps from a plié, externally rotated from the hip or "turned out" (TO). Testing dancers from a SS may not indicate activity specific power. This study's purpose was to determine differences in jump height and leg explosiveness, as measured by reactive strength index-modified (RSI-mod) when performed from TO and SS positions in dancers and non-dancers. Thus far, five healthy participants who are physically active at least ten hours/week have been studied; three dancers, having at least four years of ballet training (19.3±2.1 yrs, 66.7±11.7 kg, 1.70±0.05 m), and two non-dancers (24.5±3.5 yrs, 71.0±2.5 kg, 1.70±0.03 m). Post warm-up, participants performed three jumps from both TO and SS conditions. Time to take-off was determined as the time difference between the beginning of the eccentric lowering phase and take-off. Jump height was measured with a Vertec. RSI-mod was higher for TO than SS for dancers (0.70±0.18 vs 0.64±0.23), and similar for SS vs. TO for non-dancers (0.41±0.11 vs. .40±0.08). Dancers appear to have greater leg power overall than non-dancers, and generate more power in the TO vs. SS condition as indicated by higher jump heights and RSI-mod. Testing dancers from a TO position improves VJ performance.
