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Sex differences in blood flow restricted isotonic knee extensions to fatigue.
J Sports Med Phys Fitness. 2013 Aug; 53(4):444-52.JS

Abstract

AIM

It has been shown that females have greater muscular endurance than males and that this advantage is eliminated when blood flow is restricted. It is unknown if sex differences in dynamic endurance exist during low-load blood flow restricted (BFR) resistance exercise. The purpose of this study was to investigate sex differences in quadriceps femoris fatigability during isotonic knee extension exercise coupled with a blood flow restriction.

METHODS

Ten males and ten females completed three sets of low-load isotonic knee extension exercises (20% of peak torque) to volitional failure under two conditions: blood flow restricted (BFR) and non-restricted free flow (FF). The number of repetitions, exercise volume, post-exercise strength loss and surface electromyography (EMG) were measured.

RESULTS

Females performed more repetitions than males in the FF (252±37 vs. 112±17 repetitions; P<0.01) and BFR conditions (165±29 vs. 79±8 repetitions; P<0.01). Both sexes performed ~30% fewer repetitions during the BFR condition. MVC torque decreased approximately 37% following both conditions (P<0.01) and EMG activity increased (P<0.05) during the exercise bouts.

CONCLUSION

Similar fatigue characteristics were evident in FF and BFR conditions for both sexes, and females demonstrated greater endurance, as determined by the number of repetitions completed, in both conditions. It may be beneficial to increase the relative exercise load for females in order to decrease the time under BFR.

Authors+Show Affiliations

Department of Kinesiology, University of New Hampshire, Durham, NH, USA - summer.cook@unh.edu.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

23828293

Citation

Labarbera, K E., et al. "Sex Differences in Blood Flow Restricted Isotonic Knee Extensions to Fatigue." The Journal of Sports Medicine and Physical Fitness, vol. 53, no. 4, 2013, pp. 444-52.
Labarbera KE, Murphy BG, Laroche DP, et al. Sex differences in blood flow restricted isotonic knee extensions to fatigue. J Sports Med Phys Fitness. 2013;53(4):444-52.
Labarbera, K. E., Murphy, B. G., Laroche, D. P., & Cook, S. B. (2013). Sex differences in blood flow restricted isotonic knee extensions to fatigue. The Journal of Sports Medicine and Physical Fitness, 53(4), 444-52.
Labarbera KE, et al. Sex Differences in Blood Flow Restricted Isotonic Knee Extensions to Fatigue. J Sports Med Phys Fitness. 2013;53(4):444-52. PubMed PMID: 23828293.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Sex differences in blood flow restricted isotonic knee extensions to fatigue. AU - Labarbera,K E, AU - Murphy,B G, AU - Laroche,D P, AU - Cook,S B, PY - 2013/7/6/entrez PY - 2013/7/6/pubmed PY - 2013/12/18/medline SP - 444 EP - 52 JF - The Journal of sports medicine and physical fitness JO - J Sports Med Phys Fitness VL - 53 IS - 4 N2 - AIM: It has been shown that females have greater muscular endurance than males and that this advantage is eliminated when blood flow is restricted. It is unknown if sex differences in dynamic endurance exist during low-load blood flow restricted (BFR) resistance exercise. The purpose of this study was to investigate sex differences in quadriceps femoris fatigability during isotonic knee extension exercise coupled with a blood flow restriction. METHODS: Ten males and ten females completed three sets of low-load isotonic knee extension exercises (20% of peak torque) to volitional failure under two conditions: blood flow restricted (BFR) and non-restricted free flow (FF). The number of repetitions, exercise volume, post-exercise strength loss and surface electromyography (EMG) were measured. RESULTS: Females performed more repetitions than males in the FF (252±37 vs. 112±17 repetitions; P<0.01) and BFR conditions (165±29 vs. 79±8 repetitions; P<0.01). Both sexes performed ~30% fewer repetitions during the BFR condition. MVC torque decreased approximately 37% following both conditions (P<0.01) and EMG activity increased (P<0.05) during the exercise bouts. CONCLUSION: Similar fatigue characteristics were evident in FF and BFR conditions for both sexes, and females demonstrated greater endurance, as determined by the number of repetitions completed, in both conditions. It may be beneficial to increase the relative exercise load for females in order to decrease the time under BFR. SN - 0022-4707 UR - https://www.unboundmedicine.com/medline/citation/23828293/Sex_differences_in_blood_flow_restricted_isotonic_knee_extensions_to_fatigue_ L2 - http://www.minervamedica.it/index2.t?show=R40Y2013N04A0444 DB - PRIME DP - Unbound Medicine ER -