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. 2019 Apr 10;10:363. doi: 10.3389/fphys.2019.00363

Table 4.

Trajectory groups for middle distance swimmers by demographic characteristics, swim specialty and time-variant covariates.

Trajectory groups for Middle Distance swimmers
Long group Stable group Balanced group Unstable group P
Qualitative covariates: sample size (%)
Total 66 (100) 36 (100) 47 (100) 35 (100)
Gender female 25 (38) 18 (50) 20 (43) 18 (51) 0.50
Male 41 (62) 18 (50) 27 (57) 17 (49)
Specialty freestyle 11 (46) 16 (44) 24 (51) 15 (43) 0.10
Breaststroke 2 (3) 4 (11) 2 (4) 1 (3)
Butterfly 3 (5) 6 (17) 5 (11) 8 (23)
Backstroke 3 (5) 6 (17) 7 (15) 8 (23)
4 strokes 16 (24) 6 (17) 9 (19) 6 (17)
Quarter 2nd 35 (53) 10 (28) 23 (49) 18 (51) 0.08
3rd 31 (47) 26 (72) 24 (51) 17 (49)
Season from entry in the study 1 0 (0) 5 (14) 5 (11) 2 (6) 0.02
2 8 (12) 6 (17) 8 (17) 12 (34)
3 10 (15) 3 (8) 5 (11) 5 (14)
≥4 48 (73) 22 (61) 29 (62) 16 (46)
Season in quadrennial Post-Olympic 20 (30) 8 (22) 10 (21) 8 (23) 0.01
World Championship 16 (24) 7 (19) 13 (28) 12 (34)
Pre-Olympic 19 (29) 14 (39) 6 (13) 13 (37)
Olympic 11 (17) 7 (19) 18 (38) 2 (6)
Quadrennial September 1992–September 1996 5 (8) 5 (14) 7 (15) 7 (20) 0.20
September 1996–September 2000 7 (11) 6 (17) 7 (15) 11 (31)
September 2000–September 2004 27 (41) 11 (31) 12 (26) 9 (26)
September 2004–September 2008 18 (27) 11 (31) 12 (26) 5 (14)
September 2008–September 2012 9 (14) 3 (8) 9 (19) 3 (9)
Quantitative covariate: Mean ± SD
Age at the performance date in y 20.8 ± 3.1 19.9 ± 3.0 21.0 ± 3.4 19.8 ± 3.1 0.20

Values are sample sizes (row percentages) for categorical covariates and mean ± SD for quantitative covariates. P-values correspond to chi-squared or Fisher exact test (if chi-squared conditions not fulfilled) for categorical covariates, ANOVA or Kruskal–Wallis rank sum test (if ANOVA conditions not fulfilled) for quantitative covariates.