The acute: chronic workload ratio and injury occurrence among South African PSL soccer players

White, Ryan Colin (2019-07)

Thesis (PhD)--Stellenbosch University, 2019.

Thesis

ENGLISH ABSTRACT: Purpose: Soft-tissue, non-contact injuries (STNCI) are the most prevalent injuries in professional soccer. Considerable research has focussed on injury prevention and training load (TL) monitoring, however, the multifactorial nature of injury occurrence is often neglected. As such, both internal and external TL were examined in this study with the intention of enhancing current understanding of the mechanisms behind STNCI. The acute:chronic workload ratio (ACWR) was used to model the internally and externally derived workloads, providing a dynamic representation of preparedness and subsequent injury risk. This study aimed to identify and describe the association of both internal and external workload variables and injury risk in the subsequent week using the ACWR among professional South African Premier Soccer League (PSL) players. Article one: Article one examined the association between internally-derived TL (session rating of perceived exertion [sRPE]) and injury risk in the subsequent week utilising the ACWR and 1-, 2-, 3- and 4-weekly cumulative TL. TL data was collected from 41 professional male soccer players over one and a half seasons. In total, 85 STNCIs were recorded. Only the ACWR was significantly associated (p<0.05) with injury in the subsequent week. The workload-injury relationship was sigmoidal (s-shaped) in nature. An increased injury risk in the subsequent week was found at moderate-low (0.77-0.89; OR: 1.67, 95% CI: 1.23-2.27) and high (>1.14; OR: 1.26, 95% CI: 1.06-1.50) ACWR zones, while a low (<0.77; OR: 0.29, 95% CI: 0.14-0.61) ACWR zone exhibited a most likely beneficial effect compared to a moderate-high ACWR zone. Article two: Article two investigated the association between externally-derived (global positioning systems [GPS] and accelerometer-derived mechanical load indicators) and injury likelihood in the subsequent week utilising the ACWR. Total distance (TD), high intensity speed (HIS), high intensity acceleration (HIA) and high intensity deceleration (HID) data, was collected from 37 professional male soccer players over one and a half seasons. The workload-injury relationship was sigmoidal (s-shaped) and quadratic (u-shaped) in nature. Increased injury likelihood for the subsequent week was identified at high {(TD; >1.30, OR: 1.78, 95% CI: 0.72-4.38)(HIS; >1.41, OR: 1.74, 95% CI: 0.80-3.77)(HIA; >1.41, OR: 1.80, 95% CI 1.00-3.24)}, moderate-high (HID; >1.37, OR: 0.80, 95% CI 0.39- 2.76) and low (HIA; <0.77, OR: 1.29, 95% CI 1.00-1,66) ACWR zones, when compared to a moderate ACWR (~0.91 to ~1.20) zone. Conclusion: The workload-injury relationship was sigmoidal in nature and players exposed to acute de-loads and spikes in TL experienced an increased risk of subsequent injury. A moderate ACWR of between ~0.91 to ~1.20 represents the most realistic, optimal TL index to maintain or improve fitness and/or preparedness, while limiting injury likelihood. The similar sigmoidal nature of injury risk between internally and externally derived TL implies that sRPE may be a useful alternative to costly GPS systems in the world of injury prevention for soccer players - which is of significant importance in a South African context. Key words: Acute:chronic workload ratio, session rating of perceived exertion, global positioning systems, training load monitoring, team sport.

AFRIKAANSE OPSOMMING: Doel: Sagte weefsel, nie-kontak beserings (SWNKB) is die mees heersende beserings wat in professionele sokker voorkom. Aansienlik baie navorsing het op die voorkoming van beserings en inoefeningslading (IL) monitering gefokus, maar die multifaktoriese aard in die voorkoms van beserings word baie keer afgeskeep. As sulks is beide interne en eksterne IL in hierdie studie nagevors met die voorneme om die huidige kennis van die meganismes agter SWNKB uit te brei. Die akute:kroniese werklading ratio (AKWR) is gebruik om die interne en eksterne afgeleide werkladings te ontwerp en om ’n dinamiese voorstelling van voorbereiding en daaropvolgende beseringsrisiko te voorsien. Die huidige studie het gepoog om die assosiasie van beide interne en eksterne werklading veranderlikes en die risiko van beserings te identifiseer en te bespreek in die daaropvolgende week deur die AKWR onder professionele Suid-Afrikaanse Primier Sokkerliga (PSL) spelers te gebruik. Artikel een: Artkel een het die assosiasie tussen intern-afgeleide IL (sessie gradering van waargenome inspanning [sGWI]) en die risiko van beserings ondersoek deur van die AKWR en 1-, 2-, 3- en 4-weeklikse kumulatiewe IL gebruik te maak. IL data is by 41 professionale manlike sokkerspelers oor ʼn periode van een en 'n halwe seisoen ingesamel. In totaal is 85 SWNKB’s aangeteken. Slegs die AKWR was betekenisvol (p<0.05) geassosieer met beserings in die daaropvolgende week. Die werklading beserings verhouding was sigmoïdaal (s-vorming) van aard. ʼn Verhoogde beseringsrisiko in die daaropvolgende week was matig-laag (0.77-0.89; OR: 1.67, 95% CI: 1.23-2.27) en hoë (>1.14; OR: 1.26, 95% CI: 1.06- 1.50) AKWR sones, terwyl ‘n lae (<0.77; OR: 0.29, 95% CI: 0.14-0.61) AKWR sone die mees waarskynlike voordelige effek in vergelyking met 'n matig hoë AKWR sone getoon het. Artikel twee: Artikel twee het die assosiasie tussen ekstern afgeleide (globale posisionering sisteme [GPS] en versnellingsmeter afgeleide meganiese lading aanwysers) en die waarskynlikheid van beserings in die daaropvolgende week ondersoek deur van die AKWR gebruik te maak. Totale afstand (TA), hoë intensiteit spoed (HIS), hoë intensiteit versnelling (HIV) en hoë intensiteit spoedvermindering (HISv) data is by 37 professionale manlike sokkerspelers oor ʼn periode van een en ʼn halwe seisoen versamel. Die werklading besering verhouding was sigmoïdaal (s-vormig) en kwadraties (u-vormig) van aard. Die waarskynlikheid van ʼn verhoogde moontlikheid vir beserings in die daaropvolgende week is as hoog geïdentifiseer {(TA; >1.30, OR: 1.78, 95% CI: 0.72-4.38)(HIS; >1.41, OR: 1.74, 95% CI: 0.80-3.77)(HIV; >1.41, OR: 1.80, 95% CI 1.00-3.24)}, matig-hoog (HISv; >1.37, OR: 0.80, 95% CI 0.39-2.76) en laag (HIV; <0.77, OR: 1.29, 95% CI 1.00-1,66) AKWR sones, wanneer dit met ‘n matige AKWR (~0.91 to ~1.20) sone vergelyk. Gevolgtrekking: Die werklading beseringsverhouding was sigmoïdaal van aard en spelers wat aan akute verminderde werkladings en skielike toenames in IL blootgestel was, het ʼn verhooge risiko van daaropvolgende beserings ervaar. 'n Matige AKWR van tussen ~0.91 tot ~1.20 verteenwoordig die mees realistiese en optimale IL indeks om fiksheid en/of voorbereidheid te handhaaf of te verbeter terwyl die waarskynlikheid van beserings verminder. Die soortgelyke sigmoïdale aard van beseringsrisiko tussen intern- en ekstern-afgeleide IL impliseer dat sGWI ʼn nuttige alternatief is vir duur GPS sisteme in die wêreld van beseringsvoorkoming vir sokkerspelers - wat van betekenisvolle belang in ʼn Suid-Afrikaanse konteks is.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/106133
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