Age‐related differences in kinematics and kinetics of sprinting in young female

Abstract

This study aimed to investigate the age-related differences in sprinting performance, kinematic and kinetic variables in girls aged between 7.0 and 15.3 years.Step-to-step spatiotemporal variables and ground reaction impulses during sprinting were collected in 94 Japanese girls across a 50 m inground force plate system. From the results, a difference in rate of development in sprinting performance in girls over 12.7 years compared with younger girls (YG) was observed. The older girls (OG) became slightly slower each year (−0.09 m/s/y) compared to the YG (0.24 m/s/y) who increased their running speed. Moreover, height increased by 6.3 cm/y in YG and only 3.6 cm/y in OG, while step length during the maximal speed phase increased by 0.08 m/y in YG and plateaued in OG (0.01 m/y). Propulsive impulse during the initial acceleration phase was the kinetic variable to differ in rate of development between the age groups with an increase of 0.024 Ns/y in the YG compared to −0.010 Ns/y in OG. The development of sprinting ability in Japanese girls was more rapid before age 12.7 years. The difference in rate of development in sprinting ability can be primarily attributed to greater growth rates in YG, contributing to increases in the propulsive impulse during the initial acceleration phase and step length during the maximal speed phase. The limited gains in step length and the propulsive impulse in OG may reflect their reduced growth rate in height and the fact that increases in fat mass with maturation impaired relative force production.

The effect of biological maturity status on ground reaction force production during sprinting

“…The mechanisms behind such adaptations could include the previously observed age-related increases in musculotendon unit stiffness 31 and enhanced stretch reflex 32 in children. The finding of increased propulsive impulse, which may be augmented by the aforementioned enhanced stretch-shortening ability, mirrors that of previous studies 5,7 where this was associated with age-related sprint performance enhancements due to increased step length.…”

“…Additionally, these were associated with improvements in antero-posterior force production allowing more effective reversal of the braking phase to more rapidly generate higher propulsive impulse. Collectively, previous research has revealed two general periods of rapid development (from ages 5-8 years and age 11/12 onwards, the latter occurring around PHV) using both cross-sectional 1,[5][6][7]21 and longitudinal study designs. [2][3][4]22 Given the limited age ranges of participants in this study and due to the fact that girls on average mature earlier than boys, only one of these periods of rapid development was captured for each sex in this study.…”

“…[1][2][3][4][5][6] However, this second phase of accelerated development may not necessarily occur in girls. 3,7 Although both sexes will exhibit increases in muscle mass across this phase, girls will naturally accrue greater fat mass during puberty, compromising their force-generating capacity relative to body mass and therefore sprint capacity. 8 The aforementioned growth-related gradient of the development of sprint ability, which has been attributed to increases in propulsive forces and step length, 5,7 implicates maturity status as an important factor to consider when assessing junior athletes' progression.…”

“…3,7 Although both sexes will exhibit increases in muscle mass across this phase, girls will naturally accrue greater fat mass during puberty, compromising their force-generating capacity relative to body mass and therefore sprint capacity. 8 The aforementioned growth-related gradient of the development of sprint ability, which has been attributed to increases in propulsive forces and step length, 5,7 implicates maturity status as an important factor to consider when assessing junior athletes' progression. Indeed, early-maturing Belgian soccer players have been shown to have higher sprint performance levels compared with on-time or late-maturing players of the same chronological age.…”

Relationship between Running Spatiotemporal Kinematics and Muscle Performance in Well-Trained Youth Female Athletes. A Cross-Sectional Study

“…Some of these variables have also been associated with the prevalence of running-related injuries [16][17][18][19] together with growth-related factors, such as maturity offset and, more specifically in female athletes, the interrelationship of energy availability, menstrual function, and bone mineral density defined as the Female Athlete Triad [20,21]. The relationship between maturity offset and running biomechanics has been widely reported in sprint [22][23][24][25] and, more sparingly, in the distance running [26].…”