El Sentido de la práctica para el GCB – Núcleo Restrepo

2.5.1 Performance decrements are evident hours to days following team sport exercise.

In contrast to the nature of in-session fatigue, the fatigue following exercise cessation can persist for hours to days following team sport activity (Hoffman, Nusse et al. 2003; Ascensao, Rebelo et al. 2008; Oliver, Armstrong et al. 2008; McLean, Coutts et al. 2010), with the recovery of performance falling somewhere along a recovery continuum (Figure 2.1).

Immediate recovery (minutes following exercise

cessation)

Intermediate recovery (hours following exercise

cessation)

Prolonged recovery (days following exercise

cessation)

Figure 2.1: Recovery continuum.

Some of the in-session fatigue, may be recovered with a short rest period, whereas other components of fatigue may require hours to days to recover due to significant glycogen depletion and possibly sub optimal ionic regulation, probably due to muscle damage (Section 2.6). Further, as discussed in Section 2.6.9, muscle soreness may contribute to a reduced neural drive during this recovery period.

Reductions in performance tests conducted during the post competition/training period highlight the degree of fatigue present. Soccer specific, non-motorised treadmill exercise (42 min), elicits immediate decrements in squat jump (-3%), drop jump (-4%) and countermovement jump (CMJ) (-5%) test performance (Oliver, Armstrong et al. 2008). A greater degree of performance decrement occurs immediately after actual soccer competition, where lower limb strength (~ -10-15%) and sprint test performance (-7%) are reduced

(Ascensao, Rebelo et al. 2008). Female soccer players also experience post game declines in squat jump and CMJ test performance 24 hr following competition (Hoffman, Nusse et al. 2003). Elite AF athletes experience similar reductions in test performance as soccer players immediately after competition. Specifically, CMJ flight time (-4%), mean power (-9%), relative mean power (-8%), relative mean force (-2%) and flight time:contraction time (FT:CT) (-17%) are substantially depressed immediately post game (Cormack, Newton et al. 2008a). What’s more, test performance decrements in these elite AF athletes are still evident 24 hr later with all CMJ variables still depressed (-3% to -17%). These athletes had still not recovered three days after competition, where CMJ mean (-6%) and relative (-6%) power were still lower than baseline (Cormack, Newton et al. 2008a). Similarly, in the 48 hr following elite rugby league competition, players experienced reductions in CMJ FT, with CMJ test performance recovery occurring within four days following competition (McLean, Coutts et al. 2010).

Tournament scenarios where multiple competition games are conducted in a short period of time elicit similar levels of fatigue to single game/training sessions. In the scenarios described below, the level of fatigue measured through performance tests does not appear to accumulate to a greater extent compared to after a single exercise bout. For example a three day international handball tournament caused reductions in CMJ performance (-7%) and 20 m sprint performance (-4%) (Ronglan, Raastad et al. 2006a). Similarly, athletes experienced reductions in knee extension strength (-8%) and jump height (7%) after a five day handball training camp (Ronglan, Raastad et al. 2006a). Line drill ability (-0.4%), 20 m sprint (-1%), agility (-2%), and sit and reach (5%) performance also decreased in state level basketball players following three games separated by 24 hr (Montgomery, Pyne et al. 2008b).

An accumulation of fatigue is not always present during hockey tournaments (Spencer, Bishop et al. 2005; Jennings, Cormack et al. 2011). Such discrepancies may be due to differences in recovery time permitted or movement analysis approach. Time motion analysis through video footage suggests fatigue accumulation is evident during an elite, three game, international hockey tournament, played over four days (Spencer, Rechichi et al. 2005). The locomotive profile of these elite athletes changed across the tournament, reflecting this fatigue. In particular, athletes spent more time standing and striding, with the number of repeated sprints and time spent jogging decreased across the tournament (Spencer, Rechichi et al. 2005). Yet when elite hockey players participated in a world class hockey tournament, with six games played over nine days, exercise intensity, measured using 5 Hz GPS, was maintained (Jennings, Cormack et al. 2011). The inclusion of recovery days separating games two and three, three and four, and four and five may account for this difference compared to the former study, with only one rest day separating games one and two. It is also possible that different tactical strategies or analysis methods could explain the differences between these studies (Rampinini, Coutts et al. 2007). High level junior soccer players also display accumulated fatigue during a four day tournament. Indeed, repeated match-play in a tournament led to decrements in several match-performance variables (total distance and high-intensity running distance) and subjective ratings of fatigue and recovery (Rowsell, Coutts et al. 2011).

In contrast to the more transient fatigue observed during exercise (Section 2.3), force deficits due to changes in muscle function may persist for hours to days, and are observed following team sport exercise (Section 2.5.1). This prolonged fatigue is not exclusively related to a reduced availability of high energy phosphates, associated metabolites or Ca2+ regulation, as these variables return close to homeostatic values within 10-60 min (Harris, Edwards et al. 40

1976; Edwards, Hill et al. 1977; Hill, Thompson et al. 2001; Petersen, Murphy et al. 2005). Additionally, prolonged fatigue is unlikely entirely the result of changes in neuromuscular transmission or excitation of the sarcolemma, as voluntary activation (VA) remains unchanged in most exercise scenarios (Edwards, Hill et al. 1977; Baker, Kostov et al. 1993). Instead the slow recovery of depleted glycogen stores associated with exercise induced muscle damage (EIMD) (Section 2.6.3) and disruption to the musculature also through EIMD (Section 2.6.1) are likely causes of prolonged dampened force generation. It is important to note that damage to the musculature may influence the ability to regulate ionic balance, which may indirectly contribute to a prolonged reduction in force generating capacity during subsequent exercise bouts. It is customary to make a distinction between exercise induced muscle fatigue and muscle damage, although unquestionably the two phenomena overlap (Allen, Lamb et al. 2008). This review acknowledges the link between the two, particularly as recovery from both muscle damage and fatigue may take hours to days, however for the purpose of this review, each area is addressed separately. A reduced neural drive may also contribute to a more prolonged depression in force generating capacity through the influence of post exercise muscle soreness (Section 2.6.9). The prolonged duration to recover between sessions becomes problematic when multiple high intensity and damaging exercise sessions are conducted in close proximity, such as the schedule of AF athletes (Cormack, Newton et al. 2008a), particularly if depleted glycogen stores are not recovered. Indeed recovery of muscle structures from exercise induced muscle damage (EIMD) may take 1-3 days (Friden, Sjostrom et al. 1983; Newham, McPhail et al. 1983) as indicated by streaming, broadening and total disruption to the sarcomere Z-lines following eccentric exercise (Friden, Sjostrom et al. 1983). Such muscle injury is likely to elicit prolonged force depression through damage to cellular structure and contents (Friden, Sjostrom et al. 1983; Newham, McPhail et al. 1983; 41

Jones, Newham et al. 1986; Clarkson and Tremblay 1988; Stauber, Clarkson et al. 1990; Friden and Lieber 1992; Gibala, MacDougall et al. 1995; Hortobagyi, Houmard et al. 1998; Lieber and Friden 1999; Friden and Lieber 2001).