The increased training and playing demands on modern rugby union players can result in compromised recovery, which may lead to injury or decreased performance. Although little specific research is available on the normal training and recovery processes in rugby players, it is well known that each game places high physical demands on players (13,14). During a game, rugby players are expected to cover large distances at high exercise intensities (14), defend and tackle opponents, jump and wrestle for the ball (13), and perform a variety of high-intensity tasks over an 80-minute period. It is therefore common for rugby players to suffer considerable muscle trauma (indicated by high creatine kinase [CK] activity) during a game (21). Insufficient recovery from rugby games or training can result in fatigue, which, among other things, has been shown to affect the tackling technique and increase the risk for injury (20). The most effective recovery strategy for such athletes is unclear, but many players and coaches are using compression garments in the perceived view that these garments give them an advantage in recovery and subsequent training and competition.
Whether compression garments have any effect on performance is a matter of considerable debate. Previous research suggests that the effect of compression garments, worn during exercise, on performance is unclear, with beneficial effects mainly reported in subjects completing anaerobic and explosive forms of exercise (31), with little or no beneficial effect usually reported in aerobic performance studies (1,11). However, it has been suggested that compression garments may be more appropriate as a recovery aid, to be worn after exercise, rather than a tool to be worn during exercise (2). In this regard, Chatard et al. (7) reported that wearing compression garments improved short-term (i.e., after 80 minutes) performance recovery compared with controls. Similarly, in studies using compression garments over longer recovery periods, beneficial effects have also been found. For example, compared with a noncompressive placebo garment, multisport athletes wearing compression garments for 24 hours improved subsequent 40-km time trial cycling performance (12).
Recently, Duffield et al. (16) had rugby players complete consecutive days of rugby-specific circuits (80-minute duration) wearing compressive or normal rugby garments (controls) during and 15 hours after exercise. Although not statistically significant, Duffield et al. reported an increase in the mean peak power exerted during an explosive tackle exercise in the compressive group (4.4%) compared with a decrease of 1.5% in the controls. In addition, mean sprint performance improved for the compression group (1.0%) compared with the control group (−2.3%). Compression garments have also been associated with reduced signs of muscle soreness during recovery. Compared with a passive recovery group (seated for 9 minutes), players wearing compression garments for 12 hours after a competitive rugby match showed a substantial decrease in CK activity 36 and 84 hours after match (21). Similarly, CK activity was also substantially reduced after wearing compression garments compared with control garments for 24 hours after a cricket-specific exercise test (17).
Bench press power was recently reported to be significantly higher in strength-trained subjects after wearing compression garments compared with control garments for 24 hours (33), but others have failed to find any beneficial effect of wearing compression garments for 24 hours on force recovery (15). Montgomery et al. (37) found that wearing compression garments (compared with control) up to 18 hours postexercise, during a 3-day basketball tournament, improved the recovery of a number of measures (line drill ability, vertical jump, subjective fatigue, muscle soreness), but also reported that some measures were substantially worse (20-m speed, sit-and-reach). However, the effect of compression garments worn for a prolonged period on recovery of specific indices of rugby performance has yet to be examined.
To date, only 4 studies have been conducted into the long-term effect of compression garments on recovery in team sports performance (16,17,21,37). One of these studies failed to measure performance change after the recovery period (21), whereas others concentrated on muscle strength or explosive power performance change (17,21,37). Only 1 study (16) has investigated the effect of wearing compression garments on repeated sprint performance; however, the garments were only worn for 15 hours into recovery, possibly reducing their effectiveness. Consequently, little is known about the long-term effect (at least 24 hours) of wearing compression garments on performance recovery. Therefore, the aim of this study was to determine the effects of wearing either a compression garment or a similar-looking placebo garment over a 24-hour recovery period on subsequent physiological and performance measures in well-trained male rugby union players. It was hypothesized that compression garments would enhance recovery, thereby improving repeated sprint and 3-km run performance. It was also hypothesized that there would be a positive influence of compression garments on physiological responses during and after the performance tests.
Experimental Approach to the Problem
Compression garments are becoming increasingly popular with team sport athletes. However, little evidence exists as to their effectiveness in promoting subsequent performance recovery, particularly after high-intensity training sessions or actual sport games. This study used a single-blind crossover experiment to determine the effect of wearing compression garments, compared with wearing noncompression control garments during 24 hours, on physiological measures and performance recovery in rugby union players. This within-group design allowed each subject to serve as his own control. Each participant completed a series of exercise circuits designed to simulate a game of rugby followed 24 hours later by a 40-m repeated sprint test (10 sprints at 30-second intervals) and a 3-km run. In a randomized counterbalanced design, participants were asked to wear commercially available full–leg length (from ankle to hip) compression garments (Sport Skins Classic; Skins, Sydney, Australia—76% Meryl Elastane, 24% Lycra) or a noncompressive control garment (Ronhill Vizion Contour; RonHill, Cheshire, United Kingdom—92% Polyamide [nylon], 8% Lycra) during the 24-hour recovery period between the rugby simulation and the performance tests. After a 1-week washout period, groups were reversed and participants completed the training and testing again. The garments were only put on after the initial rugby simulation was completed in normal training attire (top and shorts); therefore, we feel confident that the experimental effect evaluated in this study is the ability of the garments to cause change during the recovery period. Additionally, in an attempt to blind the participants as to the type of garment being worn, participants were informed that the study was to compare 2 types of compression garment. A familiarization trial was completed 1 week before testing. The familiarization consisted of a complete run-through of the experimental procedures.
Twenty-two well-trained male rugby union players (age 20.1 ± 2.1 years; stature 182.1 ± 5.5 cm; body mass 88.4 ± 8.8 kg) gave their written informed consent to participate in the study according to the guidelines of the institutional human ethics committee (Lincoln University, Christchurch, New Zealand). The study was approved by the university human ethics committee and was in accordance with the Declaration of Helsinki for human research. All participants had accumulated at least 3 years of rugby-specific training, were in their precompetition phase, and were similarly matched in rugby ability (most either provincial or national age-group representatives). All participants had equal training volume, were trained by the same physical conditioner (3–4 training sessions per week), and were tested together in March 2010.
The participants were asked to refrain from intense exercise and alcohol for 24 hours prior, and from caffeine 4 hours before each main trial. Participants also recorded their dietary intake 24 hours before each trial and were asked to replicate this diet before subsequent trials. Participants were advised on ideal hydration techniques to ensure euhydration for all testing sessions and were instructed to refrain from taking any painkilling medication during the study. No other therapeutic medications were reported by the participants. Participants were also asked to ensure at least 8 hours sleep was taken before each testing day. All experimental testing took place on a grass rugby pitch, under similar climatic conditions and at the same time of the day (1700–1900 ± 1 hour) to minimize diurnal biological variation. All participants were given similar encouragement to perform maximally in all tests. In a randomized single-blind crossover experiment, players wore a full–leg length compressive garment (n = 11, Sport Skins Classic; Skins) or a similar-looking noncompressive placebo garment (n = 11, Ronhill Vizion Contour; RonHill; Figure 1) for 24 hours after performing a series of circuits developed to simulate a game of rugby. After a 7-minute warm-up consisting of 5 minutes of slow jogging and 2 minutes of dynamic and static stretching, participants were asked to complete the modified version of the rugby-specific circuit test. The rugby-specific circuit test is based on time-motion analysis studies of real first-class match play (13), and has been reported in detail elsewhere (40). In brief the test consists of repetitions of a circuit containing a range of activities characteristic of rugby match play including sprinting (straight-line and agility sprints), tackling, peak power generation in 2 consecutive scrum drives, passing accuracy, and rest periods (walking). Participants completed a total of 12 circuits each composed of 14 stations with a 10-minute break after circuit 6 to simulate halftime (total exercise time ∼84 minutes). Participants were able to drink water at halftime or full-time periods. Immediately after the rugby-specific test (completed in normal rugby shorts and t-shirt), participants were individually fitted with compression or placebo garments according to the manufacturer’s instructions and asked to wear the garments for the next 24 hours. If participants had to remove the garments (i.e., to shower), we asked that they put them back on as soon as possible. The absolute pressure exerted by the garments on the participant’s lower limbs (mean of 3 values) was measured immediately after garments were donned with a bandage pressure monitor (Kikuhime; MediTrade, Soro, Denmark) at 3 standard anthropometric sites of mid-trochanterion-tibiale laterale, mid-calf, and 10 cm above the sphyrion on the right limb while the athlete was in the standing position. One week later at the same time of day and under similar environmental conditions, the groups were reversed and the testing repeated. All participants were familiarized with all the testing protocols to be used in the study in preliminary testing and training sessions.
After the 24-hour recovery period, participants removed the garments and completed (in rugby shorts and t-shirt) a 7-minute warm-up consisting of 5 minutes of slow jogging and 2 minutes of dynamic and static stretching, followed by a 40-m repeated sprint test (10 sprints at 30-second intervals). After 10-minute rest, participants completed a 3-km running time trial to gauge the effect of each garment on performance recovery. Compression and placebo garments then remained off for any further testing. We chose these tests because previous research has indicated that anaerobic glycolytic (repeated 40-m repeated sprint) and aerobic (3-km run) energy systems are important in rugby players in all positions (13), and short sprinting surges and prolonged jogging are common in rugby match play (10) and are therefore essential in overall rugby performance. Times (to the nearest 0.01 seconds) for each sprint were recorded using 2 sets of electronic speed-timing lights (Speed-Light; Swift Performance Equipment, Goonellabah, Australia). Participants in performance-matched pairs began each sprint 30 cm behind the first set of timing lights. The 3-km time was recorded manually on a stopwatch (S120-4020; Seiko, Tokyo, Japan). Over the 10 repetitions, the fastest (RSbest) and average (RSmean) sprint times were noted and then used in the following equation to calculate fatigue: 100 − ([RSmean/RSbest] × 100) (22).
Resting blood samples were taken by venipuncture from the antecubital vein before and 24 hours after the modified rugby-specific circuit test and analysed by an independent professional testing laboratory (MedLab, Christchurch, New Zealand) for total plasma CK measured spectrophotometrically at 340 nm and 37° C using a Roche Hitachi Modular P800 analyzer (Roche Diagnostics Corp., Indianapolis, IN, USA). All participants were asked to drink >500 ml of water 1 hour before blood tests. Heart rate was recorded continuously throughout the time trial (S610; Polar, Kempele, Finland). Blood lactate concentration (Lactate Pro; Arkray Inc., Kyoto, Japan) was sampled from a finger prick ∼1 minute after the repeated sprint test and 3-km time trial. Participants were asked to score the amount of soreness perceived in both legs when completing a full squat movement on a visual analogue scale (5), immediately before, and 24 and 48 hours after the modified rugby-specific circuit test.
Analysis was performed using a specifically designed spreadsheet available for crossover studies (26). We used a contemporary statistical approach (28) because small performance changes can be beneficial for elite athletes (27), whereas conventional statistics can be less sensitive to such small but worthwhile changes. From the spreadsheet, we used magnitude-based inferences about effect sizes (ESs), and then to make inferences about true (population) values of the effect, the uncertainty in the effect was expressed as 90% confidence limits. Changes and errors were expressed as percents via analysis of log-transformed values, to reduce bias arising from nonuniformity of error (24) and, where appropriate, back-transformed to obtain changes in means in raw values (28). The probability that the true value of the effect was practically detrimental, trivial, or beneficial accounted for the observed difference and typical error of measurement (4). The smallest worthwhile change in performance was assumed to be a change of ∼1.0% (38). For the other physiological measures, the value was determined by multiplying the baseline between-subject SD by Cohen’s value of the smallest worthwhile effect of 0.2 (9). Quantitative chances of beneficial or detrimental effects were assessed qualitatively as follows: <1%, almost certainly not; 1–5%, very unlikely; 5–25%, unlikely; 25–75%, possible; 75–95%, likely; 95–99%, very likely; and >99%, almost certain. If the chances of having beneficial/better or detrimental/poorer performances were both >5%, the true difference was assessed as unclear (4). Effect sizes for the performance and physiological measures were calculated in the spreadsheets and the following threshold values were chosen for the Cohen effect statistic: <0.2, trivial; 0.2–0.49, small; 0.–0.79, moderate; and ≥0.8, large. We used a spreadsheet (25) to calculate the number of participants required in the study with the smallest worthwhile change in performance being 1.0% and the typical error or within-subject SD in similar tests of 1.1% (23). Using a type 1 error of 0.5% and a type 2 error of 25%, the number of participants in a crossover design was calculated to be 10. Reliabilities of the dependent measures using intraclass correlations were 0.80 and 0.86 for the first and second series of 40-m sprints and 0.80 for the difference in the 3-km run.
Compared with the placebo garment, wearing the compression garment produced substantially higher tissue pressures (compression: 8.6 ± 2.6, 13.4 ± 2.0, and 9.0 ± 2.2 mm Hg; placebo: 2.6 ± 1.2, 5.0 ± 1.5, and 3.5 ± 0.9 mm Hg [raw means ± SD] for the sphyrion, mid-calf, and mid-trochanterion sites, respectively).
Analysis revealed that compression had a positive effect on sprint times (Figure 2). Effect size for the mean and best sprint times were considered as small and trivial, respectively (Table 1). Differences in the fatigue between garments were considered moderate, whereas differences between garments for the 3-km run were considered small. Qualitative analysis confirmed that wearing compression garments during recovery had a small but likely beneficial effect on 3kmtime, with the chances that the true values were beneficial/unclear/detrimental at 79/20/1% (Figure 3). Wearing compression garments was also likely to be beneficial for fatigue (85/14/1%), and possibly beneficial for RSmean (52/46/1%), but unclear for RSbest (13/86/1%). Observed SEs (typical or within-subject error) of measurement for the experimental measures were as follows: 3kmtime 3.7%, RSmean 2.7%, and fatigue 3.0%. The 90% confidence limits for the true errors were ∼x/÷1.3 for all measures.
Wearing compression garments compared with placebo garments during recovery had a small effect on 3kmHRmean and RSLa but otherwise trivial effects on 3kmHRmax and 3kmLa. Qualitative analysis confirmed that compression garments had a likely beneficial/positive effect on 3kmHRmean, with the chances that the true values were beneficial/unclear/detrimental of 84/14/1% (Figure 4). Qualitative analysis also confirmed that small but possibly worthwhile differences between the compression and placebo groups were found for 3kmLa (55/44/3%) and RSLa (55/41/3%). However, wearing a compression garment compared with a placebo garment had an unclear effect on 3kmHRmax, with the chances that the true values were beneficial/unclear/detrimental of 33/43/23%.
Creatine kinase activity was similar at baseline in both groups (compression: 391.7 ± 311.9 U·L−1; placebo 375.6 ± 191.4 U·L−1, raw mean ± SD). Twenty-four hours after performing the modified rugby-specific circuit test, CK levels were substantially higher in both groups (compression: 612.1 ± 312.6; placebo: 645.8 ± 384.7), but the between-group difference (33.7 ± 97.3, mean ± 90% confidence interval [CI]; ES = 0.10) was trivial. Muscle soreness increased from baseline in both groups, but by 48 hours, participants who wore compression garments during recovery were likely to have less severe delayed onset muscle soreness (DOMS) compared with wearing placebo garments (−42.4%; 90% CI, 26.8 to −177.1; ES = 0.34).
The present study is unique because it is the first study to our knowledge that has compared the effect of wearing a compression garment versus a similar-looking placebo control garment on subsequent repeated sprint and endurance performance. In agreement with our hypothesis, compared with the placebo garment, wearing a compression garment for 24 hours after high-intensity exercise (rugby simulation) was associated with better repeated sprint and endurance performance. These results confirm the beneficial effect of wearing compression garments during recovery and suggest that wearing such garments may be an effective means of recovery in rugby players.
Although compression garments are becoming increasingly popular with many team sports including rugby, there remains little evidence-based research on the effects of such garments on performance, particularly when worn as a recovery aid. Previous research indicated that relative to controls, the repeated sprint ability of rugby players was 2.2% higher (although reported as nonsignificant) the day after wearing compression garments for 15 hours postexercise. Others have also found improvements or decrements in performance after wearing compression garments during recovery (19,37). A major issue with many of the previous studies is the failure to use appropriate controls. Previous researchers have instructed participants either to wear the compression garment or their normal exercise attire. The influence of any subjective perceived benefit from the experimental intervention (compression) is therefore not accounted for in the research design and may have influenced the results (8). Findings from the current study, using a more appropriate research design (using compression and placebo garments that were similar in looks and feel), indicate that compression garments may facilitate small but worthwhile advantages for players undertaking this type of recovery compared with others who wear noncompressive garments. Failure of previous studies to pick up small but worthwhile changes in performance may also be as a result of low subject numbers or higher variability in performance measures (25).
The mechanism behind the improved performance after wearing the compression garments remains unclear. It has been suggested that wearing compression garments after exercise acts to increase venous blood flow (via the “muscle pump” system), thereby enhancing stroke volume and cardiac output (7), which may enhance arterial muscle blood flow and subsequent recovery. We found a small but worthwhile decrease in 3kmHRmean in the compression group compared with the placebo group, which may indicate improved stroke volume subsequent to improved venous return. Indeed, recent research has reported improved venous flow in the vastus lateralis muscle as a result of wearing similar compression garments to those used in this study (11). Early clinical research indicated that pressures of up to 45 mm Hg were required to increase venous flow and attenuate symptoms associated with orthostatic hypotension (39); however, more recent research shows that substantially lower pressures can have positive effects in healthy subjects. Compression garments worn for 4 hours with a mean pressure at the ankle of ∼8 mm Hg increased mean flow velocities in the popliteal veins by 15.7% (36). Furthermore, Kraemer et al. (34) found that commercially available, reasonably low-pressure (7.6–15.4 mm Hg) hosiery was effective at reducing venous pooling in the lower legs of healthy female subjects after 8 hours of standing. Although the pressures exerted by the compression garments reported in this study (8.6 ± 2.6 mm Hg at ankle) are similar to pressures reported to have beneficial effects on venous flow (34,36), many studies have failed to record such pressures, which may explain some of the inconsistency in results (7,16,19,37). It seems that light-to-moderate compression over a prolonged period of time is required to assist the muscle pump in returning blood to the heart; however, further research is required to investigate the interaction of garment pressure and time on venous return indices.
It is likely that the simulated rugby game led to significant glycogen depletion, similar to that observed in real rugby union matches (29). Such glycogen depletion potentially limits subsequent performance. Because glucose delivery via the bloodstream is an important limiting factor in muscle glycogen synthesis (30), any improvement in blood flow can hypothetically alter glucose availability to the muscle and ultimately glycogen synthesis. There is evidence to indicate that increased blood flow in athletes results in augmented glucose uptake (18). It has also been shown that glucose uptake can be increased by methacholine hydrochloride (an endothelium-dependent vasodilator) (3). We hypothesize that enhanced venous blood flow, or alternatively, pressure-related reflex arteriole vasodilatation (6), during recovery in participants wearing compression garments may have increased subsequent blood flow to areas like the skeletal muscles. The increased muscle blood flow may enhance recovery via processes such as increased glucose off load at the muscle, aerobic resynthesis of ATP, or enhanced removal of waste and cellular breakdown products. Although speculative, but similar to previous research (12), the small but qualitatively higher repeated sprint and 3-km time trial blood lactate concentration in the compression group compared with the placebo group may indicate enhanced glucose metabolism. Previous researchers have also found indicators of increased carbohydrate metabolism as a result of wearing compression garments (12). The suspected increase in carbohydrate metabolism in the compression group was not because of any change in diet but may have resulted from increased muscle glycogen storage secondary to enhanced glucose availability via the blood. However, further research taking blood flow and muscle glycogen measures into consideration is required to confirm this hypothesis.
As with actual rugby matches (21), or rugby simulations (16), we found a substantial increase in CK and DOMS from baseline up to 48 hours after testing. Compression garments, when worn during recovery, have been reported to reduce DOMS (16,37) and, in some cases, attenuate the rise of muscle damage markers such as CK (19,21). The current study found lower levels of muscle soreness (48 hours) after exercise in the compression group compared with the placebo group but no substantial difference in CK activity 24 hours postexercise. Previous studies have also noted reduced DOMS with little change in 24-hour CK levels (15,16), and we suspect that factors such as differences in blood sample collection times [Gill et al. (21) sampled at 36 and 84 hours into recovery], compression garment differences, and variation in participant’s fitness levels and exercise testing probably contribute to these dissimilarities. Kraemer et al. (32) reported attenuated CK release and reduced DOMS after eccentric exercise when wearing compression garments compared with control (no garment) and suggested that this was as a result of reduced tissue damage as a consequence of less edema. Reduced swelling with compression garments could possibly reduce the muscle damage occurring after exercise, thereby reducing the number of affected muscle fibers resulting in a reduced amount of force loss. Indeed, when we correlated the change in 3-km performance time between groups (compression − placebo) with the change in perceived muscle soreness between groups at 24 and 48 hours, we found large positive correlations (r = 0.58 and 0.71, respectively, for 24 and 48 hours) suggesting that those with more soreness were slower in the subsequent 3-km time trial.
There may be other mechanisms that are responsible for the improved performance in the compression group. There is a possibility of a placebo effect; however, we feel this is unlikely because of the study design and the fact that we told participants that both garments were compressive. Others have found altered autonomic nervous system function while wearing compression garments suggesting that mechanical stimulation of muscle afferents may also be a possibility (35).
The practical application of this study is that when worn for a 24-hour period after initial fatiguing exercise, compression garments are likely to improve subsequent performance variables that are important for well-trained rugby players. Therefore, wearing compression garments during recovery from a rugby game should benefit subsequent endurance performance and improve repeated sprint ability. We therefore suggest that compression garments should be considered along with other well-established postperformance regimes for adequate recovery.
The authors thank the volunteers in this study and acknowledge financial support from the Lincoln University Research Fund and the New Zealand Science, Mathematics and Technology Teacher Fellowship Scheme for providing a scholarship to F.D. Ward. The results of this study do not constitute endorsement of the product by the authors or the National Strength and Conditioning Association.
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