Cardiorespiratory and metabolic responses to body mass-based squat exercise in young men.
BACKGROUND
The purpose of this study was to quantify cardiorespiratory and metabolic responses to body mass-based squat exercise, with specific emphasis on the relationships with the exercise duration.


METHODS
Fifteen healthy young men performed body mass-based squat exercise as well as an incremental loaded bicycle test, which determine maximal oxygen uptake and maximal heart rate, with an interval of 2 days between the tests. During both tasks, oxygen uptake, blood lactate concentration (BLa), and heart rate (HR) were determined. Oxygen uptake in both tasks was divided by body mass (VO2). VO2in the squat task was normalized to VO2in the incremental test (%VO2max). In addition, electromyograms (EMGs) were also recorded from the vastus lateralis, rectus femoris, vastus medialis, biceps femoris, and gluteus maximus.


RESULTS
Cardiorespiratory parameters and BLa did not change after 5 min from the exercise onset. The %VO2max and BLa during body mass-based squat exercise were significantly related to maximal VO2obtained by the incremental test. Metabolic equivalents reached 6.5 when the squat exercise was continuously performed for 5 min.


CONCLUSIONS
These findings indicate that (1) the squat exercise adopted here is of moderate intensity and predominantly uses aerobic energy supply after 5 min from the start of the exercise and (2) relative intensity during the exercise depends on an individual's maximal aerobic power.
Sports and Life Science, National Institute of Fitness and Sports in Kanoya, 1 Shiromizu, Kanoya, Kagoshima, 891-2393, Japan.
Miki
M
Haramura
Sports and Life Science, National Institute of Fitness and Sports in Kanoya, 1 Shiromizu, Kanoya, Kagoshima, 891-2393, Japan. y-takai@nifs-k.ac.jp.
Yohei
Y
Takai
Japan Institute of Sports Sciences, 3-15-1 Nishigaoka, Kita-ku, Tokyo, 115-0056, Japan.
Takaya
T
Yoshimoto
Sports and Life Science, National Institute of Fitness and Sports in Kanoya, 1 Shiromizu, Kanoya, Kagoshima, 891-2393, Japan.
Masayoshi
M
Yamamoto
Sports and Life Science, National Institute of Fitness and Sports in Kanoya, 1 Shiromizu, Kanoya, Kagoshima, 891-2393, Japan.
Hiroaki
H
Kanehisa
D000328:Adult; D004576:Electromyography; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D007773:Lactates / Q000097:blood / Q000378:metabolism*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D055070:Resistance Training; D055815:Young Adult
D007773:Lactates
Aerobic metabolism; Electromyograms; Lactate threshold; Oxygen uptake; Resistance exercise