Thursday, June 23, 2011

more positive research about strength training and young athletes

Effects of Strength Training on Motor Performance Skills in Children and Adolescents: A Meta-Analysis

Pediatric Exercise Science vol 23; 2

pp. 186 – 206

The recent literature delineates resistance training in children and adolescents to be effective and safe. However, only little is known about the transfer of achieved strength gains to athletic performance. The present meta-analysis revealed a combined mean effect size for motor skill types jumping, running, and throwing of 0.52 (95% CI: 0.33–0.71). Effect sizes for each of aforementioned skill types separately were 0.54 (95% CI: 0.34–0.74), 0.53 (95% CI: 0.23–0.83), and 0.99 (95% CI: 0.19–1.79) respectively. Furthermore, it could be shown that younger subjects and nonathletes showed higher gains in motor performance following resistance training than their counterparts and that specific resistance training regimes were not advantageous over traditional resistance training programs. Finally, a positive dose response relationship for “intensity” could be found in subgroups using traditional training regimens. These results emphasize that resistance training provides an effective way for enhancing motor performance in children and adolescents.

Authors: Michael Behringer, Andreas vom Heede, Maria Matthews, Joachim Mester

Sunday, June 19, 2011

The Influence of Parachute-Resisted Sprinting on Running Mechanics in Collegiate Track Athletes

The aim of this investigation was to compare the acute effects of parachute-resisted (PR) sprinting on selected kinematic variables. Twelve collegiate sprinters (mean age 19.58 ± 1.44 years, mass 69.32 ± 14.38 kg, height 1.71 ± 9.86 m) ran a 40-yd dash under 2 conditions: PR sprint and sprint without a parachute (NC) that were recorded on a video computer system (60 Hz). Sagittal plane kinematics of the right side of the body was digitized to calculate joint angles at initial ground contact (IGC) and end ground contact (EGC), ground contact (GC) time, stride rate (SR), stride length (SL), and the times of the 40-yd dashes. The NC 40-yd dash time was significantly faster than the PR trial (p < 0.05). The shoulder angle at EGC significantly increased from 34.10 to 42.10° during the PR trial (p < 0.05). There were no significant differences in GC time, SR, SL, or the other joint angles between the 2 trials (p > 0.05). This study suggests that PR sprinting does not acutely affect GC time, SR, SL and upper extremity or lower extremity joint angles during weight acceptance (IGC) in collegiate sprinters. However, PR sprinting increased shoulder flexion by 23.5% at push-off and decreased speed by 4.4%. While sprinting with the parachute, the athlete's movement patterns resembled their mechanics during the unloaded condition. This indicates the external load caused by PR did not substantially overload the runner, and only caused a minor change in the shoulder during push-off. This sports-specific training apparatus may provide coaches with another method for training athletes in a sports-specific manner without causing acute changes to running mechanics.

Paulson, S and Braun, WA. The influence of parachute-resisted sprinting on running mechanics in collegiate track athletes. J Strength Cond Res 25(6): 1680-1685, 2011.

While positive results were shown for college track athletes, this should not necessarily be extrapolated to younger and/or non-track athletes....comments from Tony.