Compression and Recovery
While performance outcomes are often the central focus for any athlete or sport scientist, compression garments may have greater advantages to improve recovery following an exercise bout (Duffield, Cannon, and King 2010). However, to date, the evidence remains equivocal, since the two known studies comparing compressive support to other recovery methods report varying conclusions (Gill, Beaven, and Cook 2006; Montgomery, Pyne, Hopkins et al. 2008). During a 3-day basketball tournament, 29 players were assigned into three recovery groups: carbohydrate intake and stretching, cold-water immersion, and compression stockings (mean pressure 18 mmHg). Comparison of pre- and posttournament tests (sprints, agility test, vertical jumps) suggested that cold-water immersion provides the best recovery, followed by carbohydrate intake combined with stretching, and finally compression stockings (Montgomery, Pyne, Hopkins et al. 2008). However, Gill and associates (2006) compared the recovery (up to 3 days postmatch) of 23 rugby players using contrasting temperature immersion, compression garments, active recovery, and passive rest after a competitive match. Passive rest was reported to be less effective than the other three methods, which were all comparable in the rate of recovery of postmatch creatine kinase (CK) release. Accordingly, despite a lack of performance markers, Gill and colleagues (2006) concluded that compression therapy (as well as immersion and active recoveries) were effective at enhancing the rate of recovery of CK expression following exercise resulting in microdamage.
Recent studies on the effects of compression garments to assist recovery following exercise also report mixed findings. The effects on recovery of compression garments worn during exercise and up to 24 h after exercise were investigated in several studies. The benefit of wearing lower body compression garments (Duffield, Cannon, and King 2010) and full-body garments (Duffield et al. 2008) were assessed in training conditions (repeated sprints for 20 m, plyometric jumps, scrum machine, match simulations) at 24 h intervals in a population of team-sport athletes. No differences in performance (figure 11.5), maximal strength, lactate accumulation, pH, heart rate, or markers of muscle injury were observed compared to a control group, during or after recovery. In contrast, perceived pain and fatigue were significantly lower when the rugby players wore compression garments compared to normal clothing.
In another study involving cricket players in a cold environment (15 °C) (see previous section, Effects During Exercise Performance, for a description of the protocol), tests carried out after 24 h recovery revealed similar lack of differences, apart from higher skin temperatures, lower levels of markers for muscle injury, and perceived pain. In this case, wearing compression garments during the recovery phase may have assisted blunt markers of muscle damage and improved perceived recovery of soreness (Duffield and Portus 2007). These researchers also highlight a potential role for compression garments as thermal insulators in cold conditions, or when exercises are interspersed with long resting periods. However, Goh and colleagues (2011) found that compression garments in both hot and cold conditions resulted in higher skin temperatures, without differences in core temperature or ensuing effects on treadmill running performance. Accordingly, while the information on the effects of compression garments on recovery is still mixed, some benefits may be present. Although few studies outline improved recovery of performance, some evidence for reduced markers of metabolism and damage indicate potential benefits. Further, perceptual recovery following competition or training may also be assisted by use of postexercise compression.
Anaerobic Metabolite Clearance
The effect of compression garments on lactate accumulation as a marker of anaerobic clearance also remains equivocal. Berry and McMurray (1987) investigated the use of compression socks, initially designed for patients with venous insufficiency (18 mmHg at the ankle, 8 mmHg at the calf), on healthy subjects during exhausting cycling exercise. Lactate accumulation was systematically lower during recovery when compression socks had been worn during both exercise and recovery, as opposed to solely during exercise. However, there was no difference between subjects who wore compression socks or those who didn’t on ensuing recovery. This suggests that some of the influence of compressive clothing existed both during and following exercise. Further, because plasma volumes remained unchanged, the authors concluded that compression socks reduced lactate diffusion out of the muscle after exercise. In other words, lactate is retained in the intracellular matrix, and the inverted pressure gradient provided by the support may assist lactate efflux. Conversely, the same authors tested a similar protocol using elastic sport garments during running exercises on a treadmill (Berry et al. 1990). Lactate accumulation, hematocrit, oxygen consumption, and heart rate measured before and during exercise and during recovery revealed no differences among the three conditions. In this case, it would seem that the pressure exerted by the commercially available compression garments was insufficient to obtain significant results. This appears to be confirmed by recent studies reporting physiological recovery following exercise (Duffield et al. 2008, Duffield and Portus 2007).
Delayed-Onset Muscle Soreness (DOMS) Response
The studies specifically analyzing the effect of compression garments on muscle stiffness include one or more exercises with an eccentric component that is intense enough to cause muscle microinjury (Maton et al. 2006). Subjects used either compression garments or other recovery methods to investigate the benefits of compressive therapy to blunt exercise-induced DOMS response. However, as compression garments were not worn during exercise, no information was provided on how effective they are in preventing DOMS. Specifically, following 30 min downhill walking (25% slope) carrying a rucksack (12% of body weight) 8 subjects wore compression socks on one leg 5 h per day for 3 days, while the other leg served as a control. Although the exercise was perceived as low intensity by subjects, it was sufficient to induce muscle injury, as determined by decreased voluntary force, voluntary activation, and peak twitch force (Perrey et al. 2008). Moreover, wearing compression socks reduced pain at 72 h postexercise (figure 11.6) and restored neuromuscular function at a faster rate than without the garments (Perrey et al. 2008).
Similarly, beneficial effects were also reported following intense exercises involving lower (5 series of 20 step jumps) (Davies, Thompson, and Cooper 2009) and upper limbs (2 series of 50 maximal eccentric biceps contractions, including 1 maximal concentric contraction every 4 repetitions) (Kraemer et al. 2001). While wearing compression clothing did not improve recovery of muscle contractile function, levels of muscle injury markers, perceived pain and swelling, and joint flexion were all lowered. Kraemer and colleagues (2001) suggest that compression clothing may provide external pressure, limiting movement and preventing excessive damage to the contractile fibers and essentially assisting to reduce the inflammatory response. However, current evidence to support this finding remains equivocal (Maton et al. 2006; Duffield, Cannon, and King 2010). Furthermore, perceived pain has been reported to be lower following high-intensity exercise when compression garments have been worn (Duffield, Cannon, and King 2010; Duffield and Portus 2007), with trends for reductions in the inflammatory response also reported in one (Duffield and Portus 2007). However Ali and associates (2007) had previously reported that elastic tights may also impart similar perceptual benefits. Regardless, in line with previous propositions, compression garments may reduce the constraints involved in eccentric contraction by providing muscle support (Kraemer et al. 2001). Accordingly, the reduction in the direct effects of load bearing skeletal contraction may help reduce the ensuing accumulation of DOMS responses. As such, it may be of use for recovery for compression garments to be worn during exercise as well.