The Effect of Lower Extremity Compression Garments on Performance and Recovery in Endurance Sports. A Systematic Review of Randomized Trials
Written by: Michael Rosenblat
Published: December 4, 2012
Published: December 4, 2012
PLAIN LANGUAGE SUMMARY
Lower extremity compression garments (CG) have been shown to be effective in the prevention and treatment of complications in individuals with circulatory disorders including deep vein thrombosis (11), venous leg ulcers (9), lymphedema (6) and varicose veins (12). They have also been shown to be effective in limiting the degree of abnormal scarring in patients with severe burns (3). More recently CGs have been used in the athletic population to improve sport performance and to decrease recovery time.
There has been a significant increase in the use of lower extremity CGs in individuals competing in endurance sports over the past few years, with only anecdotal evidence to support their use. A recent review by MacRae et al 2011 found limited evidence to support the use of CGs during activities including jumping, sprinting and prolonged (aerobic) activities (7). Currently there are no systematic reviews of randomized controlled trials (RCT) that specifically analyze the effects of lower extremity CGs in activities that are aerobic in nature. The purpose of this review is to systematically review the available evidence of lower extremity CGs and aerobic exercise on markers of performance, recovery and perception in trained and highly-trained endurance athletes.
The outcome measures that were studied consisted of those related to performance (time to exhaustion, power output, speed), physiology (blood lactate, maximum volume of oxygen (VO2max), oxygen saturation (O2sat), and perception (rating of perceived exertion (RPE), rating of perceived soreness).
Pubmed and Medline were the databases used to perform the literature search. The search terms included: compression and exercise or compression and recovery or compression and sport. Limitations included: humans, English, randomized controlled trials.
Articles were selected if they included subjects who were involved in activities that were predominantly aerobic in nature (activities greater than two minutes in duration), lower extremity compression garments, and subjects between the ages of 18 and 65 years of age. Articles were excluded if the subjects had cardiovascular disease, had lower extremity ulcers, or included resistance training or activities less than two minutes in duration.
The literature search was conducted on August 12, 2012. Pubmed and Medline yielded a total of 166 and 136 articles respectively. Seven articles were selected following the removal of articles that did not meet the selection criteria.
The PEDro scale (score out of 10) was used to rate the quality of the articles included in this review. One study had a score of 6/10, one study scored 4/10, and five studies scored a 3/10 (Table 1).
One study investigated the effects of CGs prior to exercise, three following the completion of exercise, and four during exercise (Table 2). With respect to the type of CGs, five studies included garments that provided pressure from ankle-to-knee, in one study the garment covered only the calf, and in one study the garment provided pressure from ankle to hip (Table 2).
Are there performance benefits for individuals wearing lower extremity CGs during activities that are aerobic in nature?
Four of the seven studies analyzed the effects of wearing lower extremity (ankle to knee) CGs during exercise that was aerobic in nature (1, 2, 5, 13). The study by Kemmler et al 2009 was the only study that demonstrated benefits in aerobic performance while wearing a CG. The study included twenty-one moderately trained (VO2max 52.0 ml/kg/min ± 6.1 SD) male runners (5). Each subject performed a speed-incremented treadmill test to voluntary maximum termination while wearing a beneath-knee CG (ankle 24 mmHg, calf 18-20 mmHg) and without a CG. The intervention group demonstrated a significant (P < 0.05) increase in time to exhaustion versus the control group (36.44 ± 3.49 vs. 35.03 ± 3.55 minutes) (5).
While the results by Kemmler et al 2009 demonstrate the benefits of wearing a CG during aerobic exercise, there are a number of methodological issues of concern associated with the study design. Subjects acted as their own control, however they were not adequately blinded to the intervention (5). Therefore the performance gains associated with wearing the CGs may simply be due to the placebo effect. The authors did not mention whether all participants completed the trial or how missing data was handled, i.e. an intention-to-treat analysis (5). If there were participants excluded from the analysis of the results, the main rationale for randomization was defeated.
Are lower extremity CGs effective in improving recovery time in individuals participating in activity that is aerobic in nature?
Two studies assessed the benefits of wearing CGs during recovery (4, 8). Of the two studies, only de Glanville et al 2012 found positive changes in aerobic performance associated with wearing CGs during the recovery period. In this study fourteen trained (40-km cycling mean power output of 254±18.5 watts) multisport male athletes completed two separate bouts of a 40-km cycling time trial 24 hours apart (4). The subjects exhibited significant improvements in time-trial performance following the application of a full-length, lower extremity CG (ankle 6.0 mmHg, calf 14.7 mmHg, thigh 11.8 mmHg) for 24-hours following an initial 40-km time-trial compared to the control group (4).
The de Glanville et al 2012 study was one of a few studies that included an appropriate control environment to adequately blind subjects to the intervention. Both the intervention and control groups wore a lower extremity garment, of which only the garment in the intervention group provided compression (4). An additional strength of this study was that the subjects acted as their own control providing an accurate comparison between trials. Some limitations to this study include the small sample size (n=14), and the lack of adequate follow-up and intention-to-treat analysis (4). Due to these limitations, it is difficult to determine the accuracy of the results.
Do lower extremity CGs have an effect on physiological makers associated with activity that is aerobic in nature?
All of the studies analyzed selected physiological responses associated with wearing a CG either prior to, during or post aerobic exercise. Menetrier et al 2011 and Rimaud et al 2010 were the only two studies that demonstrated a significant physiological change associated with wearing a CG.
Menetrier et al 2011 analyzed the effects of wearing a below knee CG (medial ankle 15 mmHg, top of gastrocnemius 27 mmHg) prior to and following multiple bouts of treadmill running on fourteen, moderately-trained (average MAV 13.8±1.5 km/h at 12% slope) endurance athletes (8). The protocol included five periods that occurred consecutively: 15 minutes at rest, 30 minutes at 60% maximum aerobic velocity (MAV), 15 minutes of rest, 5 minutes at 100% MAV, and finally a 30 minute rest period (8). The subjects wore the CG during the rest periods described in the protocol above (8).
The authors found that subjects who wore a CG immediately following exercise had greater calf muscle O2sat (+7.4±1.7% and +10.7±1.8% at 20th and 30th minutes respectively) than those subjects without a CG (8). They also found that there is a dose response related to the amount of pressure applied (20 mmHg to 50 mmHg), with greater pressure leading to greater calf muscle O2sat (8). A major limitation is that the authors did not explain at what point in the protocol the pressure increments occurred. It is also important to note that subjects and assessors were not blinded to the intervention, and the authors did not mention whether there was adequate follow-up or an intention-to-treat analysis (8).
The study by Rimaud et al 2010 included eight moderately trained (VO2max 53.3±2.7 ml/kg/min) subjects who performed two incremental cycling tests to exhaustion on separate occasions (10). The subjects were randomly allocated to one of two groups, either the intervention group consisting of below knee CGs (ankle 12 mmHg, calf 28 mmHg) or the control group (no CG) (10). There was a significant (p < 0.05) increase in blood lactate (mmol/L) in the intervention group during exercise (10). This indicates that there is a negative physiological impact with the wearing of CGs during exercise, as the subjects were unable to clear lactate from their exercising muscle. There were no performance changes due to the increase lactate levels, however it is possible that elevated levels might have an affect on events that are longer in duration.
Do lower extremity CGs have an effect on perceptual markers associated with activity or recovery in exercise that is aerobic in nature?
Each of the studies included in this review analyzed the effects of CGs on perceptual markers either during or post exercise. One of the two trials, in the study by Ali et al 2007, demonstrated a significant difference in a perceptual outcome measure (1). The study included fourteen moderately trained (VO2max = 55.0±0.9 ml/kg/min) participants who took part in two separate experiments. The first consisted of two progressive shuttle-run tests, completed on separate occasions. The second involved two 10-km time trials separated by at least 3 days.
In the second experiment subjects were randomly assigned to one of two groups, one that wore a below knee CG (18-22 mmHg at the ankle, 70% less pressure at the calf), the other a control group with no CG. Subjects acted as their own controls by switching groups to complete the second time-trial. The results of the study show that the rating of perceived soreness was significantly (p < 0.05) lower in the compression group at 24-hours following the time trial (1).
As in the studies previously discussed, there are a number of methodological limitations in the current study. There was no blinding of subjects or assessors, no mention if all subjects completed the trials, and no explanation of how missing data was handled (1). The results of the study explain that subjects who wore CGs during exercise experienced less muscle soreness during the recovery period; however, it is difficult to tell if this is a result of a placebo effect.
The current review systematically analyzed randomized controlled trials on the effects of lower extremity CGs on exercise that was aerobic in nature. Only information that could be taken directly from the published studies was included in this review. Due to publishing limitations, authors are known to leave out information that they feel is less important to meet journal guidelines. Therefore, it is possible that some methodological data was left out of the critique. This review only discusses the findings of the articles that demonstrated a significant change in one of the three outcomes (performance, physiological, perceptual) described above. This was done in order to generate a more condensed review, and can be considered as a form of selection bias.
Recommendations for Future Research
The amount of research on CGs and aerobic exercise has grown significantly over the past few years. Studies of greater methodological quality are required to provide more convincing evidence on the use of CGs during activities that are aerobic in nature. Simple steps including concealed allocation and blinding of subjects and assessors can significantly increase the quality of the evidence available. It is also important to report how many subjects completed the trial and how missing data is handled. Without this information it is difficult to use the evidence discussed above to make an appropriate clinical decision.
There is low-level evidence (one RCT, PEDro 3/10) that demonstrates that wearing compression garments can improve 40km cycling time trial performance in trained male, multisport athletes.
There is moderate-level evidence (one RCT, PEDro 6/10) that demonstrates that wearing compression garments during exercise can increase calf muscle oxygen saturation during a 30-minute run in moderately-trained male athletes.
There is low-level evidence (one RCT, PEDro 3/10) that demonstrates that wearing compression garments can decrease plasma lactate levels immediately following maximal exercise in male subjects who regularly perform endurance exercise.
There is low-level evidence (one RCT, PEDro 3/10) that demonstrates that wearing compression garments can increase running time-to-exhaustion in moderately-trained male runners.
There is low-level evidence (one RCT, PEDro 3/10) that demonstrates that wearing compression garments can decrease perceived muscle soreness 24 hours following a 10km run in trained male runners.