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Clin Physiol Funct Imaging. 2013 Nov;33(6):463-9. doi: 10.1111/cpf.12054. Epub 2013 Jul 9.

Non-uniform muscle oxygenation despite uniform neuromuscular activity within the vastus lateralis during fatiguing heavy resistance exercise.

Author information

1
Faculty of Sport Sciences, Waseda University, Saitama, Japan; National Institute of Fitness and Sports in Kanoya, Kagoshima, Japan.

Abstract

Previous studies have reported for the vastus lateralis (VL) that the extent of muscle hypertrophy in response to resistance training is greater in the distal than in the middle region, despite uniform muscle fibre composition within VL along its length. In the present study, to investigate mechanism(s) for such non-uniform muscle hypertrophy, we simultaneously measured neuromuscular activity and muscle oxygenation state at the middle and distal regions of VL during fatiguing heavy resistance exercise. Twelve males performed unilateral knee extension exercise which consisted of 4 sets of 8 repetitions at intensity of 80% of the individual one repetition maximum. During the resistance exercise, neuromuscular activities and muscle oxygenation status at the middle and distal regions (50% and 70% of the thigh length, respectively) of VL were measured by using electromyography and near-infrared spectroscopy, respectively. Neuromuscular activities were similar between the distal and middle regions of VL, whereas muscle tissue oxygenation saturation was significantly lower at the distal than at the middle region of VL. These results suggest a possibility that the regional difference in muscle oxygenation but not in neuromuscular activity during fatiguing heavy resistance exercise is responsible for the regional difference in hypertrophy within a muscle.

KEYWORDS:

electromyography; hypertrophy; knee extension; near-infrared spectroscopy; resistance training

PMID:
23834101
DOI:
10.1111/cpf.12054
[Indexed for MEDLINE]

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