Coach report

Are players jumping higher over time?

Counter movement jump is important for girls football players because it’s one of the clearest, simplest windows into an athlete’s neuromuscular power and that quality underpins almost every explosive action in sport. When you measure CMJ height, you’re not just measuring how high someone can jump; you’re capturing a whole system’s ability to produce force quickly. Vescovi et al. (2011) investigated lower body power characteristics via a counter-movement jump (CMJ), observing improvements with age (under 12s [U12] and U13 had lower CMJ heights than U17–U21) in US female soccer players.

Data summary

Age and Jump Height

There is a moderate to large association between age and jump height.

As players get older they jump higher, for every year in the programme they jump 1.4 cm higher

As players get older, their jump height improves because they become stronger, more coordinated, and better able to produce explosive power.

`geom_smooth()` using formula = 'y ~ x'
`geom_smooth()` using formula = 'y ~ x'

[1] -0.09708975

`geom_smooth()` using formula = 'y ~ x'

[1] -0.09708975

`geom_smooth()` using formula = 'y ~ x'

This code filters the dataset to include only the U14 players and then visualises how each athlete’s countermovement jump (CMJ) height changes across different testing time points. First, the data is restricted to rows where the group is labelled “u14s”, ensuring that only the relevant age category is analysed. The plot then maps each time point on the x‑axis and CMJ height on the y‑axis, with each athlete represented by a separate line and colour. This allows individual progression to be tracked clearly over time. Points are added to highlight each measurement, and a minimal theme is applied to keep the visual clean and easy to interpret. The x‑axis labels are rotated to prevent overlap, and the legend is removed to avoid clutter, since each athlete already has a distinct line. Overall, the plot provides a simple and effective way to monitor CMJ development within the U14 group.