Journal of strength and conditioning research
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J Strength Cond Res · Dec 2009
Electromyographic analysis of the gluteus medius in five weight-bearing exercises.
Weight-bearing exercises are frequently used to train and strengthen muscles of the hip. These exercises have been advocated in the rehabilitation of a variety of hip and knee dysfunctions. Limited evidence is available to describe the level of muscle activation occurring with specific weight-bearing exercises. ⋯ Single limb stance places more demands on the gluteus medius than double limb stance, whereas single limb squats are more demanding than single limb stance. Although exercises performed on an Airex cushion produced greater EMG values as compared with a firm surface, the difference was not statistically significant. The results, however, suggest that if the goal is to increase the challenge to the gluteus medius, dynamic, single limb exercises performed on unstable surfaces, such as a balance cushion, may place greater demands on the gluteus medius than similar exercises performed on stable surfaces.
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J Strength Cond Res · Dec 2009
Comparative StudyThe effect of chronological age and gender on the development of sprint performance during childhood and puberty.
The purpose of the present study was to examine the effect of chronological age and gender on speed development during different sprinting phases in children and adolescents of both genders. The sample consisted of 360 sedentary pupils aged between 7 and 18 years, with 15 pupils representing each subgroup. The 30-m sprint speed was measured with photocells every 10 m. ⋯ Furthermore, the performance on each sprint phase is uniformly affected by the chronological age. Boys run faster than girls in all running phases, and the span between genders increases after the age of 15 years. It is useful that coaches take these findings into consideration when evaluating children in sprint performance.