Athletes training load and fatigue should be monitored and modified appropriately during key stages of training and competition, such as periods of intensification of work training load, accumulated training load and changes in acute training load, otherwise there is a significant risk of injury. |
Immunosuppression occurs following a rapid increase in training load. Athletes who do not return to baseline levels within the latency period (7–21 days) are at higher risk of illness during this period. |
Individual characteristics such as fitness, body composition, playing level, injury history and age have a significant impact on internal training loads placed on the athlete. Longitudinal management is therefore recommended to reduce the risk of injury and illness. |
1 Introduction
1.1 Training Load, Fatigue, Injury and Illness Definitions
1.2 Monitoring Tools
1.3 The Relationship Between Training Load and Fatigue Markers and Injury and Illness
1.4 Objectives
2 Methods
2.1 Literature Search Methodology
2.2 Search Parameters and Criteria
2.3 Assessment of Study Quality
2.4 Data Extraction and Analysis
References | Quality score/18 | Study design, hierarchical level of evidence | Sex/sport/level (n) | Injury definitiona/type | Load measures | Summary of findings |
---|---|---|---|---|---|---|
Anderson et al. [107] | 12 | Prospective cohort, 2b | Female/basketball/elite (12) | Time-loss/all injury | sRPE (training load, monotony and strain) | Pearson correlations with injury: training load, r = 0.10 (NS); strain, r = 0.68***; monotony, r = 0.67*** |
Arnason et al. [40] | 12 | Prospective cohort, 2b | Male/soccer/elite (306) | Time-loss/all injury | Training exposure | Injured group vs. non-injured, ORs: (p value) match exposure (min), >1 SD below mean 0.18 (<0.001); >1 SD above mean 0.61 (0.09); training exposure (min), >1 SD below mean 0.51 (0.07); >1 SD above mean 0.34 (0.01) |
Bengsston et al. [53] | 12 | Prospective cohort, 2b | Male/soccer/elite (27 teams) | Time-loss/muscle and ligament injury | Days between matches and number of matches | RRs, <4 days between matches vs. >6 days recovery (p value): all injury, league 1.1 (0.045), Europa League 0.7 (0.064); muscle injury, league 1.3 (<0.001), Europa League 0.5 (0.055); ligament injury, other cup 1.8 (0.041); all competition, hamstring injury 1.3 (0.011), quadriceps injury 1.8 (0.006) Linear regression, one match/month change and injury incidence/1000 h: same match sequence, muscle injury 1.6 (0.012); subsequent match sequence, total injury 2.0 (0.056) |
Brink et al. [71] | 13 | Prospective cohort, 2b | Male/soccer/elite (53) | Combined/all injury | Training and match duration, and load (sRPE) [load, monotony and strain] | Injured group vs. non-injured, ORs (p value): traumatic injury, physical stress, duration 1.14*, load 1.01*, monotony 2.59*, strain 1.01* Overuse injury, physical stress, duration 1.1 (NS), load 1.0 (NS), monotony 0.8 (NS), strain 1.0 (NS) |
Brooks et al. [27] | 12 | Prospective cohort, 2b | Male/rugby union/elite (502) | Time-loss/all injury | Training exposure | Training injury: average number and days lost per week significantly higher when total weekly training >9.1 h vs. <9.1 h Match injury: average severity and days lost per week significantly higher when total weekly training >9.1 h vs. 6.3–9.1 h |
Buist et al. [35] | 10 | Prospective cohort, 2b | Mixed/runners/novice (532) | Time-loss/all injury (running related) | Training exposure | Graded (intervention) vs. standard (control) training programme: weekly increase in running minutes +13.2 % (NS); OR for injury (95 % CI) 0.8 (0.6–1.3) [NS] |
Carling et al. [38]b
| 10 | Prospective cohort, 2b | Male/soccer/elite (1 team) | Time-loss/all injury | Match distance/min (total and >5.3 m/s) | Average m/min/match for each season and injury, Pearson correlation (p value): total m/min, severity, days r = 0.92 (0.025), number of matches r = 0.86 (0.06); >5.3 m/s m/min, muscle strain r = −0.91 (0.03) |
Carling et al. [62] | 11 | Prospective cohort, 2b | Male/soccer/elite (19) | Time-loss/all injury | Days between matches | Congested match period vs. less congested match periods: injury incidence +0.5/1000 h (0.940), severity −5.9 (0.043) |
Colby et al. [86] | 12 | Prospective cohort, 2b | Male/AF/elite (46) | Time-loss/intrinsic | Training distance, velocity and acceleration (total distance, sprint distance, V1 distance, velocity load, RVC; GPS) | Injury risk, ORs (p value), preseason: cumulative load, 3-week velocity load (6737–8046 vs. <6737 AU) 0.24 (0.04); 3-week sprint distance (846–1453 vs. < 864 m) 0.23 (0.05); 3-week total distance (73,721–86,662 vs. 73,721 m) 5.49 (0.01) Absolute change (±), force load (>556 vs. less than −13 AU) 0.10 (0.05); RVC load (0.1–9.4 vs. < 0.10 AU) 0.04 (0.006) Inseason: cumulative load, 3-week force load (>5397 vs. <4561 AU) 2.53 (0.03); 4-week RVC load (>102 vs. <84 AU) 2.24 (0.04); 2-week V1 distance (10,321–12,867 vs. 10,321 m) 0.41 (0.01), (>12,867 vs. 10,321 m) 0.28 (0.006); 2-week total distance (m). Absolute change (±), total distance (−549 to 6955 vs. −549 m) 0.49 (0.04), (>6955 vs. −549 m) 0.48 (0.08) |
Cross et al. [73] | 11 | Prospective cohort, 2b | Male/rugby union/elite (173) | Time-loss/all injury | Training load (sRPE) | Injury risk, OR (95 % CI) 1-week +1245 AU 1.7 (1.1–2.7), 1-week change +1069 AU 1.6 (1.0–2.5); 4-week load (all vs. <3684 AU), 5932–8591 AU 0.6 (0.2–1.4), >8651 AU 1.4 (1.0–2.0) |
Dellal et al. [63] | 11 | Prospective cohort, 2b | Male/soccer/elite (16) | Time-loss/all injury | Days between matches | Injury incidence/1000 h, congested vs. non-congested match periods: overall −1.2 (NS), match +24.7***, training −10*** |
Dennis et al. [56] | 12 | Prospective cohort, 2b | Male/cricket (fast bowlers)/elite (90) | Time-loss/gradual onset | Training load (days between matches and number of deliveries) | Injury rate, RRs (95 % CI) balls bowled per week (vs. 123–188 balls), <123 balls 1.4 (1.0–2.0), >188 balls 1.4 (0.9–1.6) Days between bowling sessions (all vs. 3–3.99 days) <2 days 2.4 (1.6–3.5); 2–2.99 days 1.4 (0.9–2.2); 4–4.99 days 1.3 (0.7–2.3); >5 days 1.8 (1.1–2.9) |
Duckham et al. [42] | 7 | Prospective cohort, 2b | Female/running/mixed (70) | Combined/stress fracture | Training exposure | Training exposure (h/week) in non-stress fracture group vs. case one −3, case two +7 |
Dvorak et al. [43] | 8 | Retrospective cohort, 2b | Male/soccer/mixed (264) | Combined/all injury | Training exposure | Injured vs. uninjured players: games played previous season—+0.4 (NS); total training h/week in previous preparation period +2.6*; total training h/week in previous competition period +1.5* |
Ekstrand et al. [44] | 11 | Prospective cohort, 2b | Male/soccer/elite (266) | Time-loss/all injury | Training exposure | World Cup vs. non-World-Cup players, mean difference: exposure (h/player), total +41***, training +20 (NS), matches +21*** Injury incidence (injuries/1000 h), total −1.6 (NS), training −2.3***, matches −3.6 (NS) |
Fünten et al. [45] | 10 | Prospective cohort, 2b | Male/soccer/elite (188) | Time-loss/all injury | Training exposure | Mean difference, 2009–2010 (3.5 week winter break) vs. 2008–2009 season (6.5 week winter break) post-winter break: exposure (h), total −18.4 (<0.001), training −16.7 (<0.001), match −1.6 (0.15) Injury RRs, 2009–2010 vs. 2008–2009 (p value): all, knee ligament 1.9 (0.09); training, traumatic 1.5 (0.07), minimal 1.5 (0.02), severe 1.8 (0.06), sprain/joint 1.8 (0.07), knee ligament 3.1 (0.05); match, moderate 0.6 (0.09) |
Gabbett and Domrow [106]b
| 11 | Prospective cohort, 2b | Male/rugby league/recreational (68) | Combined/all injury | sRPE (training and match load) | Monthly load (sRPE) and injury rate (per 1000 h) relationships, Pearson correlations (p value): training load r = 0.40 (0.28), match load r = 0.35 (0.44) Significantly (p < 0.05) lower training loads and higher match loads corresponded with periods of highest injury rates |
Gabbett et al. [64] | 13 | Non-RCT, 2b | Male/rugby league/elite (91) | Time-loss/non-contact soft tissue lower body | sRPE (training load) | Training load [sRPE] (95 % CI) and injury prevalence (%), when actual loads exceeded planned: preseason, 4341 (4082–4600) AU and 72 (63–81) %; early competition, 2945 (2797–3094) AU and 75 (66–84) %; late competition, 3395 (3297–3493) AU and 57 (47–67) % Training load range (sRPE) for 50–80 % likelihood of injury: preseason 3000–5000 AU, late competition 1700–3000 AU Accuracy of model for predicting injury (95 % CI) sensitivity 87.1 (80.5–91.7) %; specificity 98.8 (98.1–99.2) %; likelihood ratio positive 70.0 (45.1–108.8); likelihood ratio negative 0.1 (0.1–0.2) |
Gabbett [77] | 9 | Prospective cohort, 2b | Male/rugby league/sub-elite (79) | Combined/all injury | sRPE (training and match load) | Injury incidence, Pearson correlations: training injury, intensity (RPE) r = 0.83*; duration (min) r = 0.79*; load (sRPE) r = 0.86* Match injury, intensity (RPE) r = 0.74*; duration (min) r = 0.86*; load (sRPE) r = 0.86* |
Gabbett [78] | 11 | Non-RCT, 2b | Male/rugby league/sub-elite (220) | Sports performance and time-loss/all injury including mechanism | sRPE (training load) | Differences between 2001 and 2002/2003 preseasons (p-values): training intensity (RPE), 2003 vs. 2001 −0.3 2011***; training load (sRPE) vs. 2001, 2002 season −65 AU***, 2003 season −28 AU** Injury incidence (injury/1000 h) vs. 2001, all injury 2002 −62.3***, 2003 −78.3***, time-loss injury 2002 −3.3**, 2003 −14.4** |
Gabbett and Domrow [79] | 11 | Prospective cohort, 2b | Male/rugby league/sub-elite (183) | Time-loss/all injury | sRPE (training load) | Individual level, one unit change in log of training load/week and injury risk, OR (p value): preseason 2.12 (0.01); early competition 2.85 (0.01); late competition 1.50 (0.04) Group level, influence of one unit change in training load/week (AU) on change in injury incidence/1000 h (p value): pre-season +0.35 (0.01); early competition −0.08 (0.53); late competition +0.02 (0.84) |
Gabbett and Jenkins [80] | 14 | Prospective cohort, 2b | Male/rugby league/elite (79) | Combined/non-contact and contact and activity type | sRPE (training load) | Relationships between total, field and strength training load (sRPE) and injury, Pearson correlations: total injury, total r = 0.82**; field r = 0.67*; strength r = 0.81** Field injury, total r = 0.86**; field r = 0.68*; strength r = 0.87**; non-contact injury, total r = 0.82**; field r = 0.65*; strength r = 0.82** Contact injury, total r = 0.80**, field r = 0.63*, strength r = 0.75**; strength injury, total r = 0.59 (NS); field r = 0.43 (NS); strength r = 0.63* |
Gabbett and Ullah [34] | 11 | Prospective cohort, 2b | Male/rugby league/elite (34) | Sports performance and time-loss/non-contact soft tissue lower body | Training distance (m for various velocity thresholds and m/min; GPS) | Relative risk of injury for thresholds of training load [m/session] (threshold load value): very low intensity (>542 m), time-loss injury 0.4*; low intensity (>2342 m), time-loss injury 0.5*; very high intensity (>9 m), sports performance injury 2.7*; mild acceleration (>186 m), sports performance injury 0.2**; moderate acceleration (>217 m), sports performance injury 0.3**, time-loss injury 0.4*; maximum acceleration (>143 m), sports performance injury 0.4*, time-loss injury 0.5* |
Gabbett et al. [64] | 10 | Prospective cohort, 2b | Male/rugby league/elite (30) | Combined/collision injury | Number and intensity (g experienced; GPS accelerometer) of collisions and days between matches | Number of training collisions and training collision injury rate both significantly (p < 0.05) higher in 10-day recovery cycles between matches than <10-day recovery cycles |
Gabbett et al. [65] | 11 | Prospective cohort, 2b | Male/rugby league/elite (51) | Time-loss/collision injury | Number of collisions (coded from video footage) and days between matches | Match collisions significantly (p < 0.05) greater in wide-running position vs. all other positions, but significantly lower collision injury rate; match collision injury rate/10,000 collisions significantly (p < 0.05) higher in 8-day recovery cycles between matches than >/<8-day recovery cycles |
Hägglund et al. [46] | 10 | Prospective cohort, 2b | Male/soccer/sub-elite (26) | Time-loss/all injury | Training and match number and exposure | 2001 vs. 1982 seasons for 15 best players/team (p values): training sessions (player/year) +76 (<0.001); matches (player/year) −8 (<0.001); training exposure (h/player) +97 (<0.001), match exposure (h/player) −12 (<0.001) Injury incidence/1000 h, training +0.6 (0.63), matches +5.3 (0.45), slight −0.8 (0.53), minor +0.1 (0.86), moderate +0.5 (0.30), major −0.1 (0.65) |
Hägglund et al. [47] | 11 | Prospective cohort, 2b | Male/soccer/elite (188) | Time-loss/all injury including mechanism | Training and match number and exposure | Swedish vs. Danish 2001 spring domestic season (p values): training sessions (player/year) +34 (<0.001); matches (player/year) +1 (0.52); training exposure (h/player) +48 (<0.001); match exposure (h/player) −1 (0.23) Injury incidence, player/season, training −0.4 (0.001), matches −0.2 (0.29); 1000/h, training −5.8 (<0.01), matches −2.0 (0.59), slight −3.1 (0.088), minor −1.5 (0.014), moderate −0.5 (0.15), major −1.1 (0.002) |
Hulin et al. [57] | 13 | Retrospective cohort, 2b | Male/cricket (fast bowlers)/elite (28) | Time-loss/non-contact | sRPE (training load) and balls bowled/week | Relationship between increased training load and injury risk, RRs (p value): external load (balls bowled/week), acute (1-week), same week decreased injury (0.0001); chronic (4-week average), same week decreased injury (0.002), subsequent week decreased injury (0.02) Acute:chronic load ratio >100 % vs. <100 %, subsequent week injury, external load 2.1 (0.01); internal load 2.2 (0.009) Acute:chronic load ratio, RRs (p values), external load 200 vs. 50–99 % 3.3 (0.03), <49 % 2.9 (0.04); internal load 200 vs. 50–99 % 4.5 (0.009), <49 % 3.4 (0.03) |
Killen et al. [81] | 11 | Prospective cohort, 2b | Male/rugby league/elite (36) | Combined/all injury | sRPE (training load, monotony, strain) | Weekly load/fatigue–injury relationships, Pearson correlations (p value): load (sRPE), r = 0.02 (0.94); strain, r = 0.09 (0.78); monotony, r = 0.32 (0.28) |
Main et al. [50] | 14 | Prospective cohort, 2b | Mixed/triathlon/sub-elite (30) | Combined/all injury | Training exposure and sessions/week and perceived effort and intensity (1–5 scale) | Linear mixed model associations with signs and symptoms of injury and illness: total number of sessions/week***, swim sessions/week*, cycle sessions/week**, running sessions/week*** |
Mallo and Dellal [55] | 13 | Prospective cohort, 2b | Male/soccer/elite (35) | Time-loss/ligament sprains and muscle strains | Training heart rate, number of sessions and session frequency | Ligament sprains higher in first two training stages*; muscle strains higher in final training stage (p = 0.051) Injury incidence relationships with stage training load, Pearson correlation: heart rate r = 0.72*; training frequency r = −0.17 (NS); number of sessions r = −0.20 (NS) |
Murray et al. [66] | 11 | Prospective cohort, 2b | Male/rugby league/elite (43) | Time-loss/all injury | Days between matches | Injury incidence/1000 h for short (5–6), medium (7–8) and long (9–10) days between matches: no differences for all injuries between different cycles; significantly fewer buttock, thigh and muscular injuries after short cycles**; adjustable highest injury incidence after short cycles and hit-up forwards and outside backs after long cycles** |
Nielsen et al. [87] | 11 | Prospective cohort, 2b | Mixed/running/novice (60) | Time-loss/all injury (running related) | Training distance (GPS) | Mean differences (p value): injured increase in weekly training load vs. non-injured +9.5 % (0.07); increase in training load week before injury vs. all other weeks +86 % (0.03) |
Orchard et al. [60] | 12 | Retrospective cohort, 2b | Male/cricket (fast bowlers)/elite (129) | Time-loss/non-contact or gradual onset bowling injury | Training load (overs bowled) | 5.4 (18.8 %) more overs bowled/match in players injured in the next 28 days vs. non-injured RRs (95 % CI) injury risk for >50 overs bowled/match in the following: 14 days 1.8 (1.0–3.3); 21 days 1.8 (1.1–3.0); 28 days 1.6 (1.0–2.6) |
Orchard et al. [58] | 12 | Prospective cohort, 2b | Male/cricket (fast bowlers)/elite (235) | Time-loss/non-contact or gradual onset bowling injury | Training load (overs bowled) | RRs (95 % CI) for injury: overs bowled in time period and injury risk for following 28 days: 5 days >50 overs 1.5 (1.0–2.3), 17 days >100 overs 1.8 (0.9–3.5) |
Orchard et al. [59] | 12 | Prospective cohort, 2b | Male/cricket (fast bowlers)/elite (235) | Time-loss/non-contact or gradual onset bowling injury | Training load (overs bowled) | Tendon injury in 21 days, RRs (p value): match >50 overs 3.7 (0.001), career >12,000 overs 2.4 (0.000), previous season >400 overs 2.0 (0.000), 3 previous months >150 overs 0.3 (0.000), career >3000 overs 0.2 (0.000); bone-stress injury in 28 days, 3 previous months >150 overs 2.1 (0.000); muscle injury in 28 days, previous season >400 overs 0.7 (0.020); joint injury in 28 days, previous season >450 overs 2.0 (0.015) |
Owen et al. [67] | 13 | Prospective cohort, 2b | Male/soccer/elite (23) | Time-loss/all injury | Training heart rate (T-HI and T-VHI) | Injury and heart rate relationships (p value): Pearson correlations, T-HI, training r = 0.57 (0.005), match r = 0.09 (0.69), traumatic 0.42 (0.04), severity 0.51 (0.01); T-VHI, training r = 0.57 (0.005), match r = 0.19 (0.38), traumatic 0.44 (0.03), severity 0.47 (0.02) Forwards stepwise linear regression, T-HI and T-HVI r
2 = 0.28 (0.014); OR (p value): T-HI, match injury 1.9 (0.02) Less T-HI (p = 0.06) and T-VHI (p = 0.04) in the month before an injury did not occur vs. an injury occurring |
Piggott et al. [68] | 13 | Prospective cohort, 2b | Male/AF/elite (16) | Time-loss/all injury | sRPE (training load, monotony and strain), mins >80 % Maximum heart rate, training distance (total and > 3.3 m/s; GPS) | Injury incidence relationships, Pearson correlations (p values): load (NS), monotony r = 0.25 (NS), strain r = 0.07 (NS), distance r = −0.52 (0.05), distance >3.3 m/s (NS), time >80 % maximum heart rate (NS) Percentage of injury explained by previous spike: load, 40 %; strain, 40 %; monotony, 20 % |
Putlur et al. [84] | 13 | Prospective cohort, 2b | Female/soccer/sub-elite (14 plus 14 recreational controls) | Time-loss/all injury | sRPE (training load, monotony and strain) | Mean training load, monotony and strain and injury frequency greater in soccer vs. control group |
Rogalski et al. [85] | 12 | Prospective cohort, 2b | Male/AF/elite (46) | Time-loss/all injury | sRPE (training and match load) | Injury, ORs (p value): training load (sRPE), 1-week load all vs. <1250 AU, 1250–1750 AU 1.95 (0.06), 1750–2250 AU 2.54 (0.007), >2250 AU 3.38 (0.001); 2-week load, all vs. <2000 AU, 2000 to <3000 AU 2.93 (0.14), 3000–4000 AU 4.03 (0.05), >4000 AU 4.74 (0.03) Previous to current week change, all vs. 250 AU, 250–750 AU 1.34 (0.15); 750–1250 AU 0.89 (0.68); >1250 AU 2.58 (0.002) |
Saw et al. [61] | 10 | Prospective cohort, 2b | Male/cricket/elite (28) | Combined/throwing associated injuries | Training load (number of throws in training and matches) | Mean differences (p value): injured vs. non-injured, throws/day +12.5 (0.06), throws/week +49.7 (0.004); week before injury vs. all other weeks prior to injury, throws/week +38.9 (0.0001), throwing days/week +1.9 (0.04), rest days vs. throwing days −2.2 (0.0004) |
van Mechelen et al. [51] | 9 | Prospective cohort, 2b | Mixed/mixed/recreational (139) | Time-loss/all injury | Training exposure | Injury OR (95 % CI) for total sporting time above median (4050 h) 6.9* |
Veugelers et al. [70] | 11 | Prospective cohort, 2b | Male/AF/elite (45) | Time-loss/non-contact soft tissue injury | RPE and sRPE (all training and field training load) | High vs. low training load (above and below median), ORs for injury (p values): all training, sRPE, 1 week 0.20 (0.04), RPE, 1 week 0.20 (0.04), 2 weeks 0.23 (0.06) |
Viljoen et al. [52] | 9 | Prospective cohort, 2b | Male/rugby/elite (38) | Combined/all injury | Training load (overs bowled) | In-season, training h/match, 3-year decrease; injury rates, 3-year decrease Pre-season, training exposure, 3-year decrease*; injury rate, 3-year increase** |
References | Quality score/18 | Study design, hierarchical level of evidence | Sex/sport/level (n) | Injury definitiona/type | Fatigue measures | Summary of findings |
---|---|---|---|---|---|---|
Brink et al. [71] | 13 | Prospective cohort, 2b | Male/soccer/elite (53) | Combined/all injury | REST-Q | Injured group vs. non-injured, ORs (p value): traumatic injury, psychological stress, fitness/injury 1.3, overuse injury, psychological stress, fitness/injury 1.5 |
Dennis et al. [97] | 11 | Prospective cohort, 2b | Male/AF/elite (22) | Time-loss/all injury | Sleep exposure and efficiency (actigraphy) | Injury week vs. two weeks before injury, two-way ANOVA (p value): sleep duration (min) −23 (0.47); sleep efficiency (%) −3 (0.56); sleep duration and efficiency interaction (0.62) |
Gabbett and Domrow [106]b
| 11 | Prospective cohort, 2b | Male/rugby league/recreational (68) | Combined/all injury | Anthropometry (sum of skinfolds, height, body mass), linear speed (40-m acceleration), lower-body power (vertical jump), agility (L run), maximal aerobic power | No clear trends for anthropometry and fitness measure changes with injury rates |
Ivarsson and Johnson [37] | 9 | Prospective cohort, 2b | Male/soccer/sub-elite (48) | Time-loss/all injury | Hassles and Uplifts Scale | Injured group greater daily hassle pre-injury than non-injured group (p = 0.085) |
Ivarsson et al. [93] | 10 | Prospective cohort, 2b | Mixed/soccer/elite (56) | Time-loss/all injury | Hassles and Uplifts Scale | Path analysis: daily hassle, direct positive effect on injury frequency*** |
Ivarsson et al. [94] | 10 | Prospective cohort, 2b | Mixed/soccer/elite (101) | Time-loss/all injury | Hassles and Uplifts Scale | Change in hassle/uplift prediction of injury incidence, latent growth-curve analysis: daily hassle +0.33**; daily uplift −1.87** |
Killen et al. [81] | 11 | Prospective cohort, 2b | Male/rugby league/elite (36) | Combined/all injury | Perceptual wellness scores (sleep, food, energy, mood and stress; 1–10 scale) | Weekly fatigue–injury relationships, Pearson correlations (p value): total perceptual wellness scores r = 0.71 (0.08) |
Kinchington et al. [95] | 10 | Prospective cohort, 2b | Male/AF, rugby union and rugby league/elite (182) | Time-loss/all lower-limb injury | Lower-Limb Comfort Index (36-point questionnaire) | Relationships with Lower-Limb Comfort Index and injury, Pearson correlations: poor comfort r = 0.88***; usual comfort 0.69***; high comfort 0.39*** Injury incidence/1000 h: poor comfort 43.5; usual comfort 14.1; high comfort 2.3 |
King et al. [39]b
| 7 | Prospective cohort, 2b | Male/rugby league/recreational (30) | Sports performance and time-loss/all injury | REST-Q | Injury relationships, Pearson correlations (p value): training (sports performance injury), lack of energy r = −0.77 (0.04), physical complaints r = −0.87 (0.01), social recovery r = 0.69 (0.09), sleep quality r = 0.87 (0.01), injury r = −0.78 (0.04); match (time-loss injury), lack of energy r = −0.90 (0.005), physical complaints r = −0.73 (0.07), disturbed breaks r = −0.75 (0.05); match (sports performance and time-loss injury), lack of energy r = −0.72 (0.05), physical complaints r = −0.75 (0.07), emotional stress r = −0.69 (0.08) |
Laux et al. [96] | 11 | Prospective cohort, 2b | Male/soccer/elite (22) | Time-loss/all injury | REST-Q | Injury risk month after assessment, ORs for one unit increase in REST-Q measure (p value): fatigue 1.7 (0.007), sleep quality 0.5 (0.010), disturbed breaks 1.8 (0.047), injury 1.8 (<0.001) |
Main et al. [50] | 14 | Prospective cohort, 2b | Mixed/triathlon/sub-elite (30) | Combined/all injury | PSS | Linear mixed model associations with signs and symptoms of injury and illness: PSS*** |
Piggott et al. [68] | 13 | Prospective cohort, 2b | Male/AF/elite (16) | Time-loss/all injury | Salivary IgA and cortisol | Injury incidence, Pearson correlations (p value): week 5 cortisol r = 0.73* |
References | Quality score/18 | Study design, hierarchical level of evidence | Sex/sport/level (n) | Illness definitiona/type | Load measures | Summary of findings |
---|---|---|---|---|---|---|
Anderson et al. [107] | 12 | Prospective cohort, 2b | Female/basketball/elite (12) | Time-loss/all illness | sRPE (training load, monotony and strain) | Pearson correlations with illness: training load, r = 0.10 (NS) |
Brink et al. [71] | 13 | Prospective cohort, 2b | Male/soccer/elite (53) | Time-loss/all illness | Training and match duration and load [sRPE] (load, monotony and strain) | Injured group vs. non-injured, ORs for illness (p value): physical stress, duration 1.12 (NS), load 1.00 (NS), monotony 2.52 (NS), strain 1.00 (NS) |
Cunniffe et al. [54] | 10 | Prospective cohort, 2b | Male/rugby union/elite (31) | Combined/URI | sRPE (training load) and game number | Visual trend for reduced game time and increase training load to precede clusters of URIs |
Fahlman and Engels [90] | 10 | Prospective cohort, 2b | Male/AmF/elite (75 plus 25 non-sporting controls) | Combined/URTI | Baecke Physical Activity Questionnaire | Football players vs. controls (p value): time points 2, 3, 6 and 7, higher URTI %*; all study, physical activity questionnaire, work +1 (0.78), sport +2 (0.001), leisure −1 (0.64), total +2.6 (0.003) |
Ferrari et al. [74] | 11 | Prospective cohort, 2b | Male/road cycling/sub-elite (8 plus male college athlete controls) | Combined/URI | sRPE (training load, monotony and strain) | Training strain relationships, Pearson correlations (p values): WURSS score, preparatory phase r = 0.72 (0.03), second competitive phase r = 0.70 (0.05); total URTI symptoms r = 0.73 (0.04) |
Foster [75] | 11 | Prospective cohort, 2b | Mixed/swimming/mixed (25) | Unknown/all illness | sRPE (training load, monotony and strain) | Percentage of illness explained by spike in individual training load thresholds: load 84 %, monotony 77 %, strain 89 % Percentage of excursions above individual thresholds that did not result in illness: load 55 %; monotony 52 %; strain 59 % |
Freitas et al. [76] | 11 | Prospective cohort, 2b | Male/soccer/elite (11) | Combined/URI | sRPE (training load) | Higher training load in overload vs. taper phase when URI incidence was higher |
Fricker et al. [69] | 9 | Prospective cohort, 2b | Male/running/elite (20) | Combined/all illness | Training load (distance × RPE; self-reported) | Mean training differences between week and month pre-illness and whole study average (p value): mileage (km), week −4 (0.65), month +7 (0.73); intensity (RPE), week 0.0 (0.87), month 0.0 (0.90); load (RPE·km), week −5 (0.82), month 32 (0.54); number of illnesses, Pearson correlations: weekly mileage, intensity and load r < 0.1 |
Gleeson et al. [88] | 8 | Prospective cohort, 2b | Mixed/mixed (endurance-based)/mixed (80) | Combined/all illness | MET h/week | Mean difference, ill vs. illness-free athletes (p value): training load (h/week) +2.3 (0.05) |
Hausswirth et al. [48] | 11 | Prospective cohort, 2b | Male/triathlon/sub-elite (27) | Combined/URTI | Training exposure and heart rate | Frequency of total infection cases: functional overreaching group 67 %; acute fatigue group 22 %; control group 11 % |
Mackinnon and Hooper [49] | 10 | Prospective cohort, 2b | Mixed/swimming/elite (24) | Combined/URTI | Self-reported training distance (swimming) and exposure (land-based) | Mean differences, URTI frequency, overtrained = 1/8 (12.5 %), well trained = 9/16 (56 %) |
Main et al. [50] | 14 | Prospective cohort, 2b | Mixed/triathlon/sub-elite (30) | Combined/all illness | Training exposure and sessions/week and perceived effort and intensity (1–5 scale) | Linear mixed model associations with signs and symptoms of injury and illness: total number of sessions/week***, swim sessions/week*, cycle sessions/week**, running sessions/week*** |
Moreira et al. [82] | 9 | Prospective cohort, 2b | Male/basketball/elite (15) | Combined/URTI | sRPE (training load) | Mean differences: training load (sRPE) greater in week 2 vs. week 4*; number of URTIs higher in week 2 vs. weeks 1 and 4* |
Moreira et al. [83] | 11 | Prospective cohort, 2b | Male/futsal/elite (12) | Combined/URTI | sRPE (training load) | Mean differences: training load (sRPE) greater in weeks 1 and 2 vs. weeks 3 and 4*; URTI severity greater in weeks 1 and 2 vs. week 4* URTI severity in week 4, Pearson correlation (p value): training load r = 0.87* |
Mortatti et al. [102] | 11 | Prospective cohort, 2b | Male/soccer/elite (14) | Combined/URTI | Match RPE | Mean differences: match RPE greater in matches 4, 5, 6 and 7 vs. match 1*; URTI incidence greater before match 2 and 6 vs. match 1* |
Neville et al. [91] | 12 | Prospective cohort, 2b | Male/yacht racing/elite (38) | Time-loss/URI | Combined exposure and intensity ranking (1–5 scale) | URI incidence, Pearson correlations: training exposure (sailing and training load) r = 0.002 (NS) |
Piggott et al. [68] (2008) | 13 | Prospective cohort, 2b | Male/AF/elite (16) | Time-loss/all illness | sRPE (training load, monotony and strain), mins >80 % Maximum heart rate, training distance (total and >3.3 m/s; GPS) | Illness incidence relationships, Pearson correlations (p values): load (NS), monotony r = 0.12 (NS), strain r = 0.12 (NS), distance (NS), total distance >3.3 m/s (NS), time >80 % maximum heart rate (NS) Percentage of illness explained by previous spike: load, 42 %; strain, 25 %; monotony, 33 % |
Putlur et al. [84] | 13 | Prospective cohort, 2b | Female/soccer/sub-elite (14 plus 14 recreational controls) | Time-loss/all illness | sRPE (training load, monotony and strain) | Mean training load, monotony and strain and illness frequency greater in soccer vs. control group; percentage of illness explained by previous spike in measure: increased training load 55 %, increased monotony and strain 64 % |
Veugelers et al. [70] | 11 | Prospective cohort, 2b | Male/AF/elite (45) | Time-loss/all illness | RPE and sRPE (all training and field training load) | High vs. low training load (above and below median), ORs for illness (p values): all training, sRPE, 1 week 0.30 (0.07); field training, sRPE, 1 week 0.30 (0.07), 2 weeks 0.13 (0.05), RPE, 1 week 0.18 (0.03) |
References | Quality score/18 | Study design, hierarchical level of evidence | Sex/sport/level (n) | Illness definitiona/type | Fatigue measures | Summary of findings |
---|---|---|---|---|---|---|
Brink et al. [71] | 13 | Prospective cohort, 2b | Male/soccer/elite (53) | Time-loss/all illness | REST-Q | Illness, psychological stress, emotional stress 2.27, social stress 2.07, conflicts/pressure 1.69, fatigue 1.48*, lack of energy 1.92, physical complaints 1.88, social recovery 0.66*, general well-being 0.57, sleep quality 0.58, disturbed breaks 1.51*, emotional exhaustion 1.47*, fitness/injury 1.60*, being in shape 0.56 |
Cunniffe et al. [54] | 10 | Prospective cohort, 2b | Male/rugby union/elite (31) | Combined/URI | Salivary lysozyme and IgA | Mean difference, present URI or ± 5 days from peak of symptoms vs. no URI (p value), relative IgA −15 % (0.08) |
Fahlman and Engels [90] | 10 | Prospective cohort, 2b | Male/AmF/elite (75 plus 25 non-sporting controls) | Combined/URTI | Salivary IgA, protein and osmolality | Football players vs. controls (p value): time points 2, 3, 6 and 7, lower salivary IgA*, higher URTI %* Secretion rate of salivary IgA (μg/min) and number of colds (across all study time points), stepwise multiple regression: r
2 = 0.12–0.42; p = 0.000–0.003 |
Ferrari et al. [74] | 11 | Prospective cohort, 2b | Male/road cycling/sub-elite (8 plus male college athlete controls) | Combined/URI | Salivary IgA and leukocyte | No significant differences between training phases for any salivary immune function measure |
Freitas et al. [76] | 11 | Prospective cohort, 2b | Male/soccer/elite (11) | Combined/URTI | Salivary cortisol and DALDA | URTI severity, Pearson correlation (p value): stress symptoms r = −0.70 (0.01); higher salivary cortisol in overload vs. taper phase when URTI incidence was higher |
Gleeson et al. [98] | 8 | Prospective cohort, 2b | Mixed/swimming/elite (25) | Combined/URTI | Salivary IgA | Relationships between immune function markers (early and late training phase) and illness, Pearson correlations (p value): total IgA, early r = −0.56 (0.16), late r = −0.63 (0.10); IgA1, early −0.71 (0.01), late r = 0.28 (0.76); IgA2, early r = −0.42 (0.41), late r = 0.39 (0.56); IgA1:IgA2, early r = 0.45 (0.46); late r = 0.10 (0.98) |
Gleeson et al. [99] | 9 | Prospective cohort, 2b | Mixed/swimming/elite (25) | Combined/URTI | Salivary and serum IgA/G/M and albumin, whole blood natural killer cell analysis | Median differences, infected vs. non-infected (p value): NK cell count (×109 cells/L) +0.06 (0.14); pre-exercise, salivary IgA (mg/L) +27.5 (0.36), salivary IgM (mg/L) +1.2 (0.21), salivary IgG (mg/L) +3.1 (0.69), salivary albumin (mg/L) +6.4 (0.95); post-exercise, salivary IgA (mg/L) +12.0 (0.26), salivary IgM (mg/L) +0.3 (0.97), salivary IgG (mg/L) −0.4 (0.64), salivary albumin (mg/L) +8.3 (0.69) |
Gleeson et al. [88] | 8 | Prospective cohort, 2b | Mixed/mixed (endurance-based)/mixed (80) | Combined/all illness | Blood cell counts, lymphocyte subsets, antigen-stimulated cytokine production, plasma immunoglobulins, salivary IgA | Mean difference, ill vs. illness-free athletes (p value): saliva flow rate (mL/min) −0.18 (0.004); salivary IgA secretion rate (mg/min) −31.0 (0.02); IgM (g/L) +0.45 (0.03); IL-2 production (pg/mL) +113 (0.06); IL-4 production (pg/mL) +3.9 (0.02); IL-6 production (pg/mL) +62 (0.09); IL-10 production (pg/mL) +4.4 (0.008); IFN-γ production (pg/mL) +14 (0.06) |
Hausswirth et al. [48] | 11 | Prospective cohort, 2b | Male/triathlon/sub-elite (27) | Combined/URTI | POMS, sleep duration and efficiency (actigraphy) | Frequency of total infection cases: functional overreaching group 67 %; acute fatigue group 22 %; control group 11 % |
Leicht et al. [100] | 9 | Prospective cohort, 2b | Mixed/wheelchair rugby/elite (14) | Combined/URS | Salivary IgA | Median difference in IgA secretion rate: illness vs. no illness (p = 0.19); illness within 2 weeks of sampling vs. no illness (NS) |
Mackinnon and Hooper [49] | 10 | Prospective cohort, 2b | Mixed/swimming/elite (24) | Combined/URTI | Perceptual wellness (fatigue, stress, sleep disturbance, muscle soreness; 1–7 scale), plasma glutamine | Mean differences, overtrained vs. well-trained athletes (p value): perceptual wellness ratings, increased fatigue (0.02), decreased sleep quality (0.05), increased stress (0.04); plasma glutamine, time 2 −23 %*, time 3 −26 % (NS); URTI frequency, overtrained = 1/8 (12.5 %), well trained = 9/16 (56 %) |
Main et al. [50] | 14 | Prospective cohort, 2b | Mixed/triathlon/sub-elite (30) | Combined/all illness | PSS | Linear mixed model associations with signs and symptoms of injury and illness: PSS*** |
Moreira et al. [82] | 9 | Prospective cohort, 2b | Male/basketball/elite (15) | Combined/URTI | DALDA and salivary cortisol | Mean differences: DALDA, more part A responses ‘worse than normal’ in week 2 vs. weeks 1, 3 and 4*, more part B responses ‘worse than normal’ in week 2 vs. week 4*; number of URTIs higher in week 2 vs. weeks 1 and 4* |
Moreira et al. [83] | 11 | Prospective cohort, 2b | Male/futsal/elite (12) | Combined/URTI | Salivary cortisol and IgA | URTI severity in week 4, Pearson correlation (p value): relative week 1–4 ΔIgAr = −0.86* |
Moreira et al. [101] | 9 | Prospective cohort, 2b | Male/soccer/sub-elite (34) | Combined/URTI | Salivary cortisol and IgA | Mean differences: IgA greater in training period 4* vs. training period 1; URTI symptoms lower in training periods 3–4* vs. training periods 1–2 |
Mortatti et al. [102] | 11 | Prospective cohort, 2b | Male/soccer/elite (14) | Combined/URTI | Salivary cortisol and IgA | Mean differences: decreased IgA before match 2 and 6 vs. match 1*; URTI incidence greater before match 2 and 6 vs. match 1* URTI incidence, Pearson correlations: decreases in salivary IgA, match 2 (r = −0.60)*, match 6 (r = −0.65)* |
Neville et al. [91] | 12 | Prospective cohort, 2b | Male/yacht racing/elite (38) | Time-loss/URI | Salivary IgA | URI incidence, Pearson correlations: raw IgA r = 0.11 (NS), relative IgA r = 0.54** Mean differences: relative IgA, URI vs. no URI −28 %***; lower in URI week vs. −4, +1 and +2 URI weeks***; lower −1 URI week vs. +2 URI week***; chance (%) of getting URI given relative IgA, <40 % = 48 % (23/48), <70 % = 28 % (74/263) |
Putlur et al. [84] | 13 | Prospective cohort, 2b | Female/soccer/sub-elite (14 plus 14 recreational controls) | Time-loss/all illness | Salivary IgA and cortisol | Percentage of illness explained by previous spike in measure: decreased IgA 82 %, decreased IgA and increased cortisol 55 % |