Jump performance and movement quality in 7- to 15-year-old competitive alpine skiers: a cross-sectional study

Figures & data

Figure 1. Measurement setup, with raters 1 and 2 as live raters from the frontal perspective, raters 3 and 4 as live raters from the sagittal perspective, and raters 1 and 3, who graded the quality of the movement execution post-exercise based on the video recordings from the frontal and sagittal perspectives, respectively.

Table 1. Baseline characteristics are presented as the means and 95% CIs in brackets.

	Female		Male
	U11	U16	U11	U16
n	76	85	76	64
Age (y)	9.65* (9.44 − 9.86)	13.51* (13.24 − 13.79)	9.41* (9.20 − 9.62)	13.65* (13.36 − 13.95)
Height (cm)	137.2* (135.1 − 139.2)	156.9*# (155.1 − 158.6)	137.2* (135.4 − 139.0)	162.3*# (159.2 − 165.3)
Weight (kg)	31.6* (30.5 − 33.2)	48.0* (45.9 − 50.1)	30.4* (29.3 − 31.4)	50.9* (47.9 − 53.9)
Maturity Offset (y)	−3.79* (–3.95 – –3.63)	−0.87* (–1.12 – –0.62)	−3.92* (–4.07 – –3.77)	−0.63* (–0.96 – –0.30)

Differences were defined as non-overlapping cis and were backed-up by unpaired sample t tests; significant differences, which are depicted with ^*for inter-age differences within the same sex and ^#for inter-sex differences within the same age groups.

Table 2. Jump distance presented as the mean and 95% CI in brackets.

	Female		Male
	U11	U16	U11	U16
n	76	85	76	64
Jump Distance (m)	4.39* (4.26 − 4.53)	5.37*# (5.21 − 5.53)	4.44* (4.33 − 4.55)	5.90*# (5.69 − 6.10)

Differences were defined as nonoverlapping cis and were backed-up by unpaired sample t tests, which are depicted with * for inter-age differences within the same sex and # for inter-sex differences within the same age groups.

Figure 2. Pie charts presenting the distribution of the grades for all skiers and in the U11 and U16 groups stratified by sex. Grey scales from light to medium to dark representing the grades from 1 to 2 to 3.

Table 3. A + B: Jump Distances for the U11 and U16 skiers stratified by sex and movement quality grade.

U11 (n = 152)							A
	Female (n = 76)			Male (n = 76)
Grade	1 (n = 32)	2 (n = 34)	3 (n = 10)	1 (n = 35)	2 (n = 29)	3 (n = 12)
Jump Distance (m)	4.30 (4.07 − 4.53)	4.46 (4.26 − 4.66)	4.46 (4.15 − 4.77)	4.46 (4.29 − 4.63)	4.37 (4.20 − 4.54)	4.55 (4.25 − 4.86)
U16 (n = 149)							B
	Female (n = 85)			Male (n = 64)
Grade	1 (n = 24)	2 (n = 37)	3 (n = 24)	1 (n = 15)	2 (n = 21)	3 (n = 28)
Jump Distance (m)	4.94 (4.61 − 5.27)	5.42 (5.20 − 5.65)	5.72 (5.51–5.93)	5.67 (5.25 − 6.09)	5.61 (5.28 − 5.95)	6.23 (5.91 − 6.55)

The data are presented as the means with 95% CIs in brackets.

Table 4. Inter-rater grading reliability and live- to post-exercise grading agreement based on Kendall’s coefficient of concordance (Kendall’s W).

			Kendall’s W	Agreement	p Value
Inter-Rater Grading Reliability	Live	Frontal	0.566	moderate	0.058
		Sagittal	0.575	moderate	0.037
	Post	Frontal	0.726	strong	<0.001
		Sagittal	0.693	moderate	<0.001
Live to Post-Exercise Grading Agreement	Live - Post	Frontal	0.62	moderate	0.003
		Sagittal	0.489	weak	0.598

Data availability statement

Restrictions apply to the availability of these data. Data were obtained from Swiss-Ski and are available from the authors with the permission of Swiss-Ski.