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Updated: Oct 5, 2026

Skeletal Muscle Gender Dimorphism from Proteomics
Published on: December 14, 2011
Sex differences in cardiometabolic and perceptual responses to high-intensity functional training and kettlebell
Brandon J Bullert1, Osmar Pinto Neto1, Devin L Jindrich1
1Department of Kinesiology, California State University San Marcos, San Marcos, CA, USA.
Purpose:
This study examined sex differences in cardiometabolic and perceptual responses to high-intensity functional training (HIFT) and kettlebell complexes (KC).
Methods:
Seventeen men (age = 26.9 ± 9.5 year) and 18 women (age = 22.2 ± 2.8 year) completed HIFT and KC protocols. Oxygen consumption (VO2), heart rate (HR), ventilation (VE), respiratory exchange ratio (RER), blood lactate concentration (BLa), rating of perceived exertion (RPE), and the Feeling Scale (FS) were measured during exercise.
Results:
Women demonstrated significantly higher (p ≤ 0.001) mean HR (156 ± 14 vs. 134 ± 17 b·min⁻¹), %HRmax (84 ± 8 vs. 76 ± 8), %VEmax (62 ± 16 vs. 52 ± 12), peak HR (183 ± 8 vs. 167 ± 15 b·min⁻¹), and higher RER (1.11 ± 0.08 vs. 1.05 ± 0.10) versus men. Relative VO2 (%VO2max: 62 ± 8 vs. 59 ± 10) did not differ between sexes (p = 0.285), despite men exhibiting higher absolute VO2 (1.87 ± 0.40 vs. 1.37 ± 0.26 L·min⁻¹; p < 0.001). No sex differences were revealed in BLa (p = 0.78), RPE (p = 0.78), or FS (p = 0.76). HIFT elicited significantly higher (p < 0.001) mean VO2 (%VO2max: 63 ± 8 vs. 58 ± 10), peak VO2 (%VO2peak: 81 ± 12 vs. 73 ± 11), VE (%VEmax: 61 ± 15 vs. 54 ± 14), and RER (1.11 ± 0.10 vs. 1.05 ± 0.09) versus KC.
Conclusion:
Women exhibited greater relative internal load during exercise despite similar relative VO2, suggesting a greater cardiovascular stimulus during whole-body interval training.
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