Fatigue Markers in Sport
Following on with some of our most recent posts on training load and injury/illness as we prepare to welcome Mark Roe for our August Seminar “Minimising Injury Risk and Maximising Performance in the GAA”, we will look at fatigue as a useful marker to monitor the athletes that we work in day to day, especially within the team setting.
Management of fatigue is important in mediating adaption to training and ensuring the athlete is prepared for competition. These training responses can be both positive and negative, and helps both the Strength and Conditioning and Medical staff see how the athlete is responding to the training load prescribed. Different times of the year, different objectives will always make these slightly open to interpretation of the support staff e.g. during a period of planned overreaching, the support staff will expect to have changes in fatigue markers that may be negative. Fatigue can also give us a better ability to reduce the athletes’ susceptibility to nonfunctional over-reaching, injury, and illness, by picking up signs and symptoms of difficulties to the training load early.
An excellent recent systematic review in Sports Medicine highlighted the role of fatigue on injury rates and illness in athletes. Below I have outlined some of the main findings from the review on fatigue markers and injury within that paper.
Fatigue Markers and Injury
The review showed that only 9 studies investigated fatigue–injury relationships, seven of which used perceptual wellness scales.
- In soccer players 3 studies showed greater daily hassles to be associated with increased injury, using the Hassles and Uplifts Scale (HUS) (Ivarsson et al., 2010; Ivarsson et al., 2013; Ivarsson et al., 2015)
- Laux et al. (2015) further support the positive perceptual fatigue– injury relationship in their findings, which reported that increased fatigue and disturbed breaks, as well as decreased sleep-quality ratings, were related to increased injury.
However, In contrast rating of perceptual fatigue showed slightly different findings in other studies:
- Killen et al. (2010) found increased perceptual fatigue (measured via worse ratings of perceptual sleep, food, energy, mood, and stress) was associated with decreased training injury during an elite rugby league preseason.
- Similarly, King et al. (2010) showed increased perceptual fatigue (measured via various REST-Q factors) was associated with decreased sports performance training injuries and time-loss match injuries.
The authors theorise that these unexpected findings may be due to the fact that when players perceive themselves to be less fatigued they may train/play at higher intensities, increasing injury likelihood.
Most of the studies used wellness scales that take approximately 1–4 min to complete. These are extremely practical to administer to athletes and are quick and not too time consuming. The Rest-Q has been also well-validated within the literature.
The review also showed that current self-report measures fare better than their commonly used objective counterparts. In particular, subjective well-being typically worsened with an acute increase in training load and chronic training load, whereas subjective well-being demonstrated improvement when acute training load decreased. Using quick subjective questionnaires and “knowing” the athletes is vitally important. Earning the trust of the athlete and building a strong relationship over a period of time, is just as useful as any expensive monitoring system.
The authors also noted the poor investigation within the literature of the relationship between sleep and injury. Sleep is a vital part of the body’s recovery process and has been well highlighted in recent times on it’s relationship to productivity, chronic pain and depression (Rosekind, (2010); Smith (2004); Tsuno (2005). The review showed that three studies assessed sleep–injury relationships via sleep quality ratings, with only Dennis et al. (2015) investigating objective measures of sleep quality and quantity in relation to injury. No significant differences in sleep duration and efficiency were reported between the week of injury and 2 weeks prior to injury.
While the number of studies is quiet limited in the review, evidence of the use in the team setting to monitor the role of fatigue on injuries is supported. However, anecdotally and from experience within the field the importance of speaking to people, building strong relationships and creating a supportive environment cannot be underestimated. An athlete who trusts your role and job in helping their performance and having their wellness as a priority will often speak to you sooner than any subjective or objective marker can pick up. So while using these tools is of great importance, don’t forget the strength of building personal relationships with your athletes.
- Ivarsson A, Johnson U. Psychological factors as predictors of injuries among senior soccer players: a prospective study. J Sports Sci Med. 2010;9(2):347.
- Ivarsson A, Johnson U, Podlog L. Psychological predictors of injury occurrence: a prospective investigation of professional Swedish soccer players. J Sport Rehabil. 2013;22(1):19–26. 93.
- Ivarsson A, Johnson U, Lindwall M, et al. Psychosocial stress as a predictor of injury in elite junior soccer: a latent growth curve analysis. J Sci Med Sport. 2014;17(4):366–70
- King D, Clark T, Kellmann M. Changes in stress and recovery as a result of participating in a premier rugby league representative competition. Int J Sports Sci Coach. 2010;5(2):223–37.
- Kinchington M, Ball K, Naughton G. Reliability of an instrument to determine lower limb comfort in professional football. Open Access J Sports Med. 2010;1:77–85.
- Kinchington M, Ball K, Naughton G. Monitoring of lower limb comfort and injury in elite football. J Sports Sci Med. 2010;9(4):652.
- Killen NM, Gabbett TJ, Jenkins DG. Training loads and incidence of injury during the preseason in professional rugby league players. J Strength Cond Res. 2010;24(8):2079–84.
- Laux P, Krumm B, Diers M, et al. Recovery-stress balance and injury risk in professional football players: a prospective study. J Sports Sci. 2015;33(20):2140–8.
- Rosekind, Mark R., et al. “The cost of poor sleep: workplace productivity loss and associated costs.” Journal of Occupational and Environmental Medicine52.1 (2010): 91-98.
- Smith, Michael T., and Jennifer A. Haythornthwaite. “How do sleep disturbance and chronic pain inter-relate? Insights from the longitudinal and cognitive-behavioral clinical trials literature.” Sleep medicine reviews 8.2 (2004): 119-132.
- Tsuno, Norifumi, Alain Besset, and Karen Ritchie. “Sleep and depression.” The Journal of clinical psychiatry (2005).
- Dennis J, Dawson B, Heasman J, et al. Sleep patterns and injury occurrence in elite Australian footballers. J Sci Med Sport. 2015;19(2):113–6.