Table 2 Data extraction from included studies
From: Is Cumulative Load Associated with Injuries in Youth Team Sport? A Systematic Review
Reference | Statistic | 95% Confidence interval | Statistic adjusted for covariates | Presence of association | Direction |
|---|---|---|---|---|---|
Ahmun et al. [29] | Acute WL: RR = 2.51 Chronic WL: RR = 1.48 | Acute WL: (1.70,3.70) Chronic WL: (1.01, 2.70) | Acute WL: No Chronic WL: No | Acute WL: Yes Chronic WL: Yes | Acute WL: Positive Chronic WL: Positive |
Bowen et al. [10] | Overall injuries: High TD 4-wk: RR = 1.64 Low TD 1-wk: RR = 0.25 Mod-High 4-wk HSD: RR = 2.14 Mod-High 1-wk HSD: RR = 1.73 Low HSD 1-wk: RR = 0.30 High TL 1-wk: RR = 1.65 Low TL 1-wk: RR = 0.27 Very High ACC 3-wk: RR = 3.84 Low ACC 3-wk: RR = 0.31 | Overall injuries: High TD 4-weekly: (1.05, 2.58) Low TD 1-weekly (0.11, 0.82) Mod-High HSD: (1.31, 3.50) Mod-High HSD 1-weekly: (1.06, 2.84) Low HSD 1-wk: (0.13, 0.68) High TL 1-wk: (1.04, 2.62) Low TL 1-wk: (0.12, 0.60) Very High ACC 3-wk: (1.57, 9.41) Low ACC 3-wk: (0.13, 0.76) | Overall injuries: High TD 4-wk: No Low TD 1-wk: No Mod-High HSD 4-wk: No Mod-High HSD 1-wk: No Low HSD 1-wk: No High TL 1-wk: No Low TL 1-wk: No Very High ACC 3-wk: No Low ACC 3-wk: No | Overall injuries: High TD 4-wk: Yes Low TD 1-wk: Yes Mod-High HSD 4-wk: Yes Mod-High HSD 1-wk: Yes Low HSD 1-wk: Yes High TL 1-wk: Yes Low TL 1-wk: Yes Very High ACC 3-wk: Yes Low ACC 3-wk: Yes | Overall injuries: High TD 4-wk: Positive Low TD 1-wk: Negative Mod-High HSD 4-wk: Positive Mod-High HSD 1-wk: Positive Low HSD 1-wk: Negative High TL 1-wk: Positive Low TL 1-wk: Negative Very High ACC 3-wk: Positive Low ACC 3-wk: Negative |
Brink et al. [30] | Traumatic injury: Duration: RR = 1.14 Load: RR = 1.01 Overuse injury: Duration: RR = 1.07 Load: RR = 1.01 | Traumatic injury: Duration: (1.06, 1.23) Load: (1.00, 1.02) Overuse injury: Duration: (0.98, 1.18) Load: (1.00, 1.01) | Traumatic injury: Duration: No Load: No Overuse injury: Duration: No Load: No | Traumatic injury: Duration: Yes Load: Yes Overuse injury: Duration: No Load: No | Traumatic injury: Duration: Positive Load: Positive Overuse injury: Duration: NA Load: NA |
Frisch et al. [31] | Unadjusted: OR = 1.3 Adjusted for years playing and out of season weight lifting: OR = 1.3 | Unadjusted: (1.1–1.7) Adjusted: (0.9–1.7) | Unadjusted: No Adjusted: Yes | Unadjusted: Yes Adjusted: No | Adjusted: Positive Adjusted: NA |
Hartwig et al. [32] | Training volume: OR = 1.03 Match volume: OR = 1.41 Weekly volume: OR = 1.19 | Training volume: (0.78–1.33) Match volume: (1.14–1.74) Weekly volume: (0.93–1.51) | Training volume: Yes Match volume: Yes Weekly volume: Yes | Training volume: No Match volume: Yes Weekly volume: No | Training volume: NA Match volume: Positive Weekly volume: NA |
Lathlean et al. [5] | Session load linear: OR = 0.64 Session load quadratic: OR = 1.44 1-wk load linear: OR = 0.56 1-wk load quadratic: OR = 1.43 2-wk load: OR = 1.01 3-wk load: OR = 0.99 4-wk load: OR = 0.92 | Session load linear: (0.49–0.83) Session load quadratic: (1.11–1.88) 1-wk load linear: (0.42–0.73) 1-wk load quadratic: (1.07–1.92) 2-wk load: 0.914–1.11) 3-wk load: (0.89–1.11) 4-wk load: (0.83–1.03) | Session load linear: No Session load quadratic: No 1-wk load linear: No 1-wk load quadratic: No 2-wk load: No 3-wk load: No 4-wk load: No | Session load linear: Yes Session load quadratic: Yes 1-wk load linear: Yes 1-wk load quadratic: Yes 2-wk load: No 3-wk load: No 4-wk load: No | Session load linear: Negative Session load quadratic: Bidirectional 1-wk load linear: Negative 1-wk load quadratic: Bidirectional 2-wk load: NA 3-wk load: NA 4-wk load: NA |
O'Keeffe et al. [7] | 1-wk load: OR = 2.75 2-wk load: OR = 2.57 3-wk load: OR = 2.57 4-wk load: OR = 2.57 | 1-wk load: (1.00–7.59) 2-wk load: (0.94–7.07) 3-wk load: (0.94–7.07) 4-wk load: (0.94–7.07) | 1-wk load: Yes 2-wk load: Yes 3-wk load: Yes 4-wk load: Yes | 1-wk load: Yes 2-wk load: No 3-wk load: No 4-wk load: No | 1-wk load: Positive 2-wk load: NA 3-wk load: NA 4-wk load: NA |
Orr and Cheng [33] | Weekly PA did not correlate with number of match injuries (r = − 0.03, p = 0.83) Weekly PA did not correlate with match injuries per match hour (r = − 0.07, p = 0.60) |  | Number of match injuries: No Number of match injuries per hour: No | Number of match injuries: No Number of match injuries per hour: No | Number of match injuries: NA Number of match injuries per hour: NA |
Ristolainen et al. [6] | Acute injuries | ||||
Boys: Training season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: OR = 1.57 15 + hr/wk: OR = 2.16 Competition season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: OR = 1.39 15 + hr/wk: OR = 1.67 Competitions: 7–19: ref 20–39: OR = 1.48 40 + : OR = 2.02 | Boys: Training season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: (1.06–2.32) 15 + hr/wk: (1.28–3.64) Competition season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: (0.94–2.04) 15 + hr/wk: (0.99–2.81) Competitions: 7–19: ref 20–39: (0.89–2.47) 40 + : (1.21–3.37) | Boys: Training season hrs/wk: 3–6 h/wk: No 7–14 h/wk: No 15 + hr/wk: No Competition season hrs/wk: 3–6 h/wk: No 7–14 h/wk: No 15 + hr/wk: No Competitions: 7–19: No 20–39: No 40 + : No | Boys: Training season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: Yes 15 + hr/wk: Yes Competition season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: No 15 + hr/wk: No Competitions: 7–19: NA 20–39: No 40 + : Yes | Boys: Training season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: Positive 15 + hr/wk: Positive Competition season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: NA 15 + hr/wk: NA Competitions: 7–19: NA 20–39: NA 40 + : Positive | |
Ristolainen [6] | Overuse injuries | ||||
Boys: Training season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: OR = 1.91 15 + hr/wk: OR = 2.14 Competition season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: OR = 1.64 15 + hr/wk: OR = 2.26 Competitions: 7–19: ref 20–39: OR = 1.21 40 + : OR = 1.42 | Boys: Training season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: (1.24–2.94) 15 + hr/wk: (1.24–3.71) Competition season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: (1.08–2.49) 15 + hr/wk: (1.31–3.90) Competitions: 7–19: ref 20–39: (0.71–2.06) 40 + : (0.8–2.41) | Boys: Training season hrs/wk: 3–6 h/wk: No 7–14 h/wk: No 15 + hr/wk: No Competition season hrs/wk: 3–6 h/wk: No 7–14 h/wk: No 15 + hr/wk: No Competitions: 7–19: No 20–39: No 40 + : No | Boys: Training season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: Yes 15 + hr/wk: Yes Competition season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: Yes 15 + hr/wk: Yes Competitions: 7–19: NA 20–39: No 40 + : No | Boys: Training season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: Positive 15 + hr/wk: Positive Competition season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: Positive 15 + hr/wk: Positive Competitions: 7–19: NA 20–39: NA 40 + : NA | |
Ristolainen [6] | Acute injuries | ||||
Girls Training season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: OR = 1.65 15 + hr/wk: OR = 2.04 Competition season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: OR = 1.77 15 + hr/wk: OR = 1.91 Competitions: 7–19: ref 20–39: OR = 1.29 40 + : OR = 0.92 | Girls Training season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: (1.11–2.45) 15 + hr/wk: (1.10–3.76) Competition season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: (1.17–2.67) 15 + hr/wk: (1.05–3.48) Competitions: 7–19: ref 20–39: (0.77–2.15) 40 + : (0.48–1.77) | Girls Training season hrs/wk: 3–6 h/wk: No 7–14 h/wk: No 15 + hr/wk: No Competition season hrs/wk: 3–6 h/wk: No 7–14 h/wk: No 15 + hr/wk: No Competitions: 7–19: No 20–39: No 40 + : No | Girls Training season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: Yes 15 + hr/wk: Yes Competition season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: Yes 15 + hr/wk: Yes Competitions: 7–19: NA 20–39: No 40 + : No | Girls Training season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: Positive 15 + hr/wk: Positive Competition season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: Positive 15 + hr/wk: Positive Competitions: 7–19: NA 20–39: NA 40 + : NA | |
Ristolainen [6] | Overuse injuries | ||||
Girls Training season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: OR = 1.42 15 + hr/wk: OR = 1.23 Competition season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: OR = 1.33 15 + hr/wk: OR = 1.68 Competitions: 7–19: ref 20–39: OR = 1.60 40 + : OR = 1.57 | Girls Training season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: (0.95–2.11) 15 + hr/wk: (0.66–2.30) Competition season hrs/wk: 3–6 h/wk: ref 7–14 h/wk: (0.88–2.01) 15 + hr/wk: (0.92–3.05) Competitions: 7–19: ref 20–39: (0.95–2.71) 40 + : (0.81–3.05) | Girls Training season hrs/wk: 3–6 h/wk: No 7–14 h/wk: No 15 + hr/wk: No Competition season hrs/wk: 3–6 h/wk: No 7–14 h/wk: No 15 + hr/wk: No Competitions: 7–19: No 20–39: No 40 + : No | Girls Training season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: No 15 + hr/wk: No Competition season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: No 15 + hr/wk: No Competitions: 7–19: NA 20–39: No 40 + : No | Girls Training season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: NA 15 + hr/wk: NA Competition season hrs/wk: 3–6 h/wk: NA 7–14 h/wk: NA 15 + hr/wk: NA Competitions: 7–19: NA 20–39: NA 40 + : NA | |
Visnes and Barr [34] | Total training volume: OR = 1.61 Volleyball training: OR = 1.72 Number of sets: OR = 3.88 | Total training volume: (1.10–2.36) Volleyball training: (1.18–2.53) Number of sets: (1.80–8.40) | Total training volume: Yes Volleyball training: Yes Number of sets: Yes | Total training volume: Yes Volleyball training: Yes Number of sets: Yes | Total training volume: Positive Volleyball training: Positive Number of sets: Positive |
Watson et al. [35] | Training load Univariable Daily: OR = 1.91 Prior day: OR = 1.42 Weekly: OR = 1.62 Monthly: OR = 1.13 Multivariable Daily: OR = 1.98 Prior day: OR = 1.38 | Training load Univariable Daily: (1.40–2.63) Prior day: (1.04–1.95) Weekly: (1.16–2.29) Monthly: (0.75–1.67) Multivariable Daily: (1.42–2.78) Prior day: (1.01–1.88) | Training load Univariable Daily: No Prior day: No Weekly: No Monthly: No Multivariable Daily: Yes Prior day: Yes | Training load Univariable Daily: Yes Prior day: Yes Weekly: Yes Monthly: No Multivariable Daily: Yes Prior day: Yes | Training load Univariable Daily: Positive Prior day: Positive Weekly: Positive Monthly: NA Multivariable Daily: Positive Prior day: Positive |