Wednesday Afternoon Poster presentations Posters displayed from 1:00–6:00 pm. One-hour author presentation times are staggered from 2:00–3:00 pm., 3:00–4:00 pm., and 4:00–5:00 pm.: B-31 Free Communication/Poster – Strength Testing and Training: WEDNESDAY, MAY 31, 2006 2:00 PM – 5:00 PM: ROOM: Hall B
PURPOSE: To determine whether gender differences eist in surface EMG activity of LE stabilizing muscles during single-leg landing in recreational athletes. Multiple factors have been identified to help explain the greater rate of ACL injuries in female athletes. Gender differences remain only minimally understood and to a lesser extent it is poorly understood in recreational athletes.
METHODS: 50 recreational athletes (25 m, 25 f) performed drop landings from 30.5 and 45.8 cm heights. Surface EMG was recorded from the following muscles: gluteus maximus, gluteus medius, semitendinosis, biceps femoris, VMO, medial head of gastrocnemius, and peroneus longus muscles. EMG examined relative muscle activity from 200 msec pre to 250 msec post contact. Mean and peak values were analyzed using MANOVA. Subjects performed 4 weeks of theraband exercise before returning for identical post-testing.
RESULTS: Men and women demonstrated significant differences during pre-contact in the semitendinosis on the univariate tests (p=0.023); and (p=0.046) in the multivariate tests when landing from the two heights during the pre-contact phase. Univariate tests demonstrated a significanct difference in the mean (p=0.021) on the peakwhen landing from the two heights during the pre-contact phase (p=0.016). The multivariate tests demonstrated significant differences in the gluteus medius muscle activity were also noted with training when landing from the 30.5 cm height (p=0.037), and p=0.024 on the univariate tests via Greenhouse-Geisser.
CONCLUSIONS: Inadequate hamstring and increased quadricep activity in men and women recreational athletes may contribute to more anterior tibial shear and place them at higher risk of non-contact ACL injuries. Functional training may assist in reducing this.