Maturation and Sex Differences in Neuromuscular Characteristics of Youth Athletes

Abstract

Understanding how neuromuscular factors that are associated with lower extremity injury risk, such as landing kinematics, muscle strength, and flexibility, change as children mature may enhance age-specific recommendations for injury prevention programs. The purpose of this study was to compare these factors in prepubertal, pubertal, and postpubertal male and female athletes. Subjects were classified on maturation stage (prepubertal: 16 males, 15 females, age: 9 ± 1 years; pubertal: 13 males, 12 females, age: 12 ± 3 years; postpubertal: 30 males, 27 females, age: 16 ± 2 years). Researchers measured lower extremity isometric muscle strength and flexibility and evaluated kinematics and vertical ground reaction forces (VGRFs) during a jump-landing task. Three-dimensional kinematics at initial contact (IC), joint displacements, and peak VGRF were calculated. Separate multivariate analyses of variance were performed to evaluate sex and maturation differences (α ≤ 0.05). Postpubertal females landed with less knee flexion at IC (p = 0.006) and demonstrated lower knee extension strength (p = 0.01) than prepubertal and pubertal females. Postpubertal males landed with less hip adduction displacement (postpubertal males = 12.53 ± 6.15°, prepubertal males = 18.84 ± 7.47°; p = 0.04) and less peak VGRF (postpubertal males = 1.53 ± 0.27% body weight [BW], prepubertal males = 1.99 ± 0.32% BW; p = 0.03) compared with prepubertal males. These findings suggest encouraging sagittal plane absorption and decreasing frontal plane motion at the hip, whereas maintaining quadriceps strength may be important for reducing injury risk in postpubertal athletes.

Neural, biomechanical, and physiological factors involved in sex-related differences in the maximal rate of isometric torque development

“…However, sex-differences in lower extremity musculoskeletal injury rates (DiStefano et al 2015) and falls incidences (Hess and Woollacott 2005; Stevens and Sogolow 2005) may be linked back to this critical aspect of muscle contraction (Bento et al 2010). Hannah et al (2012) explored potential neural and biomechanical factors involved in sex-differences in the maximal rate of tension development in the quadriceps, in addition to maximum strength.…”

Land Based Resistance Training and Youth Swimming Performance

“…Although this is somewhat speculative, the decrease in fat free mass (kg) and muscle mass (kg) in the male participants (p < 0.05) and lack of changes in the female participants (p > 0.05) over the 7 weeks suggests that muscle hypertrophy was not a significant factor in the increase in strength and power and that the improvements were in fact primarily due to improvements in neuromuscular efficiency [30]. There is a common perception among some swim coaches that resistance training will have a negative impact swimming efficiency due to increased drag forces resulting from excessive muscle hypertrophy and a decrease in flexibility [31].…”

Injury Prevention in Youth Football Players : Training Effects and Programme Implementation

“…The pubertal transition is an important time for learning new skills and performance development in football players 146 . Few pre-pubertal athletes show probability of high knee abduction moments associated with a high risk of injury compared to post-pubertal athletes 25,61 . Hence, in a population of growing individuals, age should be taken into account when considering risk factors for injury 25,61 .…”

“…Few pre-pubertal athletes show probability of high knee abduction moments associated with a high risk of injury compared to post-pubertal athletes 25,61 . Hence, in a population of growing individuals, age should be taken into account when considering risk factors for injury 25,61 . Additionally, growth-related injuries are also prevalent during the pubertal transition, before skeletal maturity has been achieved 33 .…”