Onset of Accelerated Muscle Deoxygenation During the 20-m Shuttle Run Test in Boys
in Pediatric Exercise SciencePurpose: This study aimed to compare the relative exercise intensity at which the onset of accelerated muscle deoxygenation occurs during the 20-m shuttle run test (20mSRT) between boys and men and to examine whether the timing of the onset of acceleration appearance is related to 20mSRT performance in boys. Methods: Twenty-four boys performed the 20mSRT, during which concentration changes in oxygenated and deoxygenated hemoglobin and myoglobin (ΔOxy-Hb and ΔDeoxy-Hb, respectively) in the m. vastus lateralis were monitored using a portable near-infrared spectroscopy device. The boys’ data were compared with those of 29 men in a previous study. Results: An onset of accelerated decrease in Δ[Oxy-Hb − Deoxy-Hb] was found in 11 of the 24 boys (45.8%) and 20 of the 29 men (69.0%) and was found at a higher relative exercise intensity in the boys than in the men. The number of laps at which the onset of acceleration occurred correlated with total laps in the boys (r = .87). Conclusions: These findings demonstrate that the onset of accelerated muscle deoxygenation during the 20mSRT occurs at a higher relative exercise intensity in boys than in men. Our findings also show that the timing of the onset of acceleration appearance is associated with 20mSRT performance in boys.
Kume is with the Department of Integrated Arts and Science, National Institute of Technology, Okinawa College, Nago, Okinawa, Japan. Iguchi is with the Department of Bioresources Engineering, National Institute of Technology, Okinawa College, Nago, Okinawa, Japan. Endoh is with the Department of Health and Physical Education, University of the Ryukyus, Nishihara, Okinawa, Japan.
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