NEUROMUSCULAR RESPONSE OF LOW BACK MUSCLES TO DIFFERENT WORKLOADS IN ADOLESCENT ROWERS Sbriccoli P 1, Merli A 1, and Felici F 1 1 Study University of Rome “Foro Italico” E-mail: paola.sbriccoli@iusm.it AIM: The aim of this study was to test the effect of different workloads on the EMG activity of Erector Spinae - ES (L4-L5 level) and Rectus Abdomen – RA in a group of adolescent rowers after a two-months training program. METHODS: Six subjects (Age: 14±0 years; Body mass: 61.4±11.8 kg; Stature: 1.69±0.07m) underwent a maximal test performed with a row ergometer, and consisting of a 1500m bout (pace: 22 strikes per minute). A week later, subjects were randomly divided into two groups each performing a sub-maximal test (two 1500bouts spaced by 5-min interval) at 55% and 75% of the maximal power obtained during the maximal test, respectively. During both maximal and sub-maximal tests the EMG activity was recorded from RA and ES bilaterally. Measurements were performed before and after a two-months training program. The EMG was full wave rectified. To provide a description of the EMG amplitude variation between the beginning and the end of each 1500m bout (maximal and sub-maximal test), for all trials the average EMG burst obtained during the first 250m has been compared with that obtained during the last 250m. RESULTS: During the maximal test, the ES and RA EMG amplitude did not vary overtime. During the sub-maximal test performed at 55%max power the ES EMG decreased between the beginning and the end of each 1500m bout, showing an EMG recovery during the 5-min interval. A similar behaviour was observed in the trials performed either before or after training. Conversely (Figure 1) in the sub-maximal test performed at 75%max power, no variation of the ES EMG amplitude was observed between the beginning and the end of each 1500m bout; moreover, the 5-min interval didn’t allow a convenient EMG recovery between subsequent bouts. CONCLUSION: The absence of an EMG recovery in the maximal test and in the sub-maximal test performed at 75%max power, along with the absence of an EMG recovery between subsequent bouts suggests that: 1) A 5-min rest between series is not enough to allow a convenient EMG recovery if the workload exceeds a target load; 2) the power corresponding to 75%max represents, in this experimental condition, the target load over which an increased risk of developing an acute low back pain could be invoked. Figure 1: ES EMG response Before and After Training during a sub-maximal test (75%max power) in one subject.
Neuromuscular response of low back muscles to different workloads in adolescent rowers
Sbriccoli P;F Felici
2010-01-01
Abstract
NEUROMUSCULAR RESPONSE OF LOW BACK MUSCLES TO DIFFERENT WORKLOADS IN ADOLESCENT ROWERS Sbriccoli P 1, Merli A 1, and Felici F 1 1 Study University of Rome “Foro Italico” E-mail: paola.sbriccoli@iusm.it AIM: The aim of this study was to test the effect of different workloads on the EMG activity of Erector Spinae - ES (L4-L5 level) and Rectus Abdomen – RA in a group of adolescent rowers after a two-months training program. METHODS: Six subjects (Age: 14±0 years; Body mass: 61.4±11.8 kg; Stature: 1.69±0.07m) underwent a maximal test performed with a row ergometer, and consisting of a 1500m bout (pace: 22 strikes per minute). A week later, subjects were randomly divided into two groups each performing a sub-maximal test (two 1500bouts spaced by 5-min interval) at 55% and 75% of the maximal power obtained during the maximal test, respectively. During both maximal and sub-maximal tests the EMG activity was recorded from RA and ES bilaterally. Measurements were performed before and after a two-months training program. The EMG was full wave rectified. To provide a description of the EMG amplitude variation between the beginning and the end of each 1500m bout (maximal and sub-maximal test), for all trials the average EMG burst obtained during the first 250m has been compared with that obtained during the last 250m. RESULTS: During the maximal test, the ES and RA EMG amplitude did not vary overtime. During the sub-maximal test performed at 55%max power the ES EMG decreased between the beginning and the end of each 1500m bout, showing an EMG recovery during the 5-min interval. A similar behaviour was observed in the trials performed either before or after training. Conversely (Figure 1) in the sub-maximal test performed at 75%max power, no variation of the ES EMG amplitude was observed between the beginning and the end of each 1500m bout; moreover, the 5-min interval didn’t allow a convenient EMG recovery between subsequent bouts. CONCLUSION: The absence of an EMG recovery in the maximal test and in the sub-maximal test performed at 75%max power, along with the absence of an EMG recovery between subsequent bouts suggests that: 1) A 5-min rest between series is not enough to allow a convenient EMG recovery if the workload exceeds a target load; 2) the power corresponding to 75%max represents, in this experimental condition, the target load over which an increased risk of developing an acute low back pain could be invoked. Figure 1: ES EMG response Before and After Training during a sub-maximal test (75%max power) in one subject.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
