title: A comparison of men's and women's strength to body mass ratio and varus/valgus knee angle during jump landings.
abstract: The purpose of this investigation was to compare valgus/varus knee angles during various jumps and lower body strength between males and females relative to body mass. Seventeen recreationally active females (age: 21.94 ± 2.59 years; height: 1.67 ± 0.05 m; mass: 64.42 ± 8.39 kg; percent body fat: 26.89 ± 6.26%; squat one-repetition maximum: 66.18 ± 19.47 kg; squat to body mass ratio: 1.03 ± 0.28) and 13 recreationally active males (age: 21.69 ± 1.65 years; height: 1.77 ± 0.07 m; mass: 72.39 ± 9.23 kg; percent body fat: 13.15 ± 5.18%; squat one-repetition maximum: 115.77 ± 30.40 kg; squat to body mass ratio: 1.59 ± 0.31) performed a one-repetition maximum in the squat and three of each of the following jumps: countermovement jump, 30 cm drop jump, 45 cm drop jump, and 60 cm drop jump. Knee angles were analysed using videography and body composition was analysed by dual-energy X-ray absorptiometry to allow for squat to body mass ratio and squat to fat free mass ratio to be calculated. Significant differences (P ≤ 0.05) were found between male and female one-repetition maximum, male and female squat to body mass ratio, and male and female squat to fat free mass ratio. Significant differences were found between male and female varus/valgus knee positions during maximum flexion of the right and left leg in the countermovement jump, drop jump from 30 cm, drop jump from 45 cm, and drop jump from 60 cm. Correlations between varus/valgus knee angles and squat to body mass ratio for all jumps displayed moderate, non-significant relationships (countermovement jump: r = 0.445; drop jump from 30 cm: r = 0.448; drop jump from 45 cm: r = 0.449; drop jump from 60 cm: r = 0.439). In conclusion, males and females have significantly different lower body strength and varus/valgus knee position when landing from jumps.
authors.affiliation: Neuromuscular Laboratory, Department of Health, Leisure and Exercise Science, Appalachian State University, Boone, North Carolina, USA.
authors.forename: Tracie L
authors.initials: TL
authors.lastname: Haines
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: McBride
authors.forename: N Travis
authors.initials: NT
authors.lastname: Triplett
authors.forename: Jared W
authors.initials: JW
authors.lastname: Skinner
authors.forename: Kimberly R
authors.initials: KR
authors.lastname: Fairbrother
authors.forename: Tyler J
authors.initials: TJ
authors.lastname: Kirby
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D001696:Biomechanical Phenomena; D001825:Body Fluid Compartments; D001835:Body Weight; D005260:Female; D006801:Humans; D007717:Knee / Q000033:anatomy & histology* / Q000502:physiology; D007719:Knee Joint / Q000502:physiology; D008297:Male; D009068:Movement; D053580:Muscle Strength; D010809:Physical Fitness; D016059:Range of Motion, Articular; D012737:Sex Factors; D016474:Weight-Bearing; D055815:Young Adult