Kollars, JM, Taber, CB, and Beyer, KS. Relative age effects in elite olympic weightlifters. J Strength Cond Res 35(5): 1223–1228, 2021—The time of year in which an athlete is born may provide an advantage developmentally for competition, known as relative age effects (RAEs). The presence of RAEs in sport may result in athletes participating less or leaving the sport early. To determine if RAEs exist in elite Olympic weightlifting, data were examined from the past 5 Olympic Games. Using retrospective competition data, a total of 953 weightlifters (595 men and 358 women) who competed in the Olympic Games between 2000 and 2016 were included in this study. Athletes were divided into lightweight, middleweight, and heavyweight for analysis. Using the subset weight classes, the observed date of birth distribution vs. the expected worldwide date of birth distribution were compared using multiple chi square tests. Relative age effects were present overall for weightlifters (χ2 = 189.428, p < 0.001), with over-representation in January (z = +12.6, 20.9%) and under-representation in June (z = −2.1, 6.3%), September (z = −3.2, 5.7%), and November (z = −3.0, 5.1%). Relative age effects were also present in men lightweight (χ2 = 74.773, p < 0.001), men middleweight (χ2 = 41.786, p < 0.001), men heavyweight (χ2 = 39.395, p < 0.001), and women lightweight (χ2 = 37.251, p < 0.001). Determining that RAEs are present in weightlifting is important because it will help maintain the amount of opportunity for all athletes regardless of when they were born in the year. Coaches should be aware of the possible advantages of training age and the effect of physical maturation as a result of these RAEs. Coaches may use this information for athlete selection, but the presence of RAEs should not discourage athletes from participating in the sport of weightlifting.

No abstract

Linear momentum, the product of body mass and velocity, is the key determinant of the outcome of collisions. In collision-based sports, such as American football, players with the greatest momentum tend to achieve more favorable outcomes during on-field collision, or tackles. Therefore, today's players are constantly seeking to increase mass without sacrificing velocity. However, no study has quantified linear momentum in American football players. PURPOSE: To examine the positional differences in linear momentum during a vertical jump in Division II college football players. METHODS: 56 male Division II college football players were assessed for height, body mass, and vertical jump. All players were categorized according to playing position into defensive back (DB), defensive line (DL), running/full back (RB), linebacker (LB), offensive line (OL), tight end (TE), and wide receiver (WR) groups; all other positions were excluded due to insufficient sample. Height and body mass were assessed using a stadiometer and digital scale, receptively. A vertical jump test was performed to determine jump height, which was then used to calculate vertical jump velocity. Vertical jump momentum (VJM) was calculated as the product of body mass and vertical jump velocity. Positional comparisons in VJM were made using one-way ANOVA with LSD post hoc comparisons. Alpha level was set a priori to p≤0.05. RESULTS: A significant main effect of position was observed for VJM (p<0.001). Post hoc tests revealed that OL (439.6±44.7 Ns) had significantly higher VJM than DB (p<0.001; 317.3±34.4 Ns), RB (p=0.001; 371.7±24.7 Ns), LB (p=0.006; 376±32 Ns), TE (p=0.013; 377.4±51.9 Ns), and WR (p<0.001; 338.6±25.0 Ns), while trending to be greater than DL (p=0.089; 406.9±59.6 Ns). Also, DL had significantly greater VJM than DB (p<0.001) and WR (p=0.001), and trended to be greater than RB (p=0.068). LB (p=0.009), TE (p=0.013), and RB (p=0.004) had significantly greater VJM than DB, but only RB trended to be greater than WR (p=0.086). CONCLUSION: While positional differences in VJM exist in collegiate American football, positions that regularly engage during game play (OL vs DL, WR vs DB, and LB vs RB vs TE) have no statistically significant differences. Therefore, these positions are most likely evenly matched when colliding on the field.