Evidence Based Recovery (Part 2): Compression Garments, Heat, & Cold

 
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Evidence Based Recovery (Part 2): Compression Garments, Heat, & Cold

Introduction. On our previous post, we reviewed the evidence for massage therapy, foam rolling and stretching on recovery. In this post, we will review the literature that evaluates the effects of compression garments, heat and cold on recovery.

 
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Compression Garments. Compression garments (CG) have been used by athletes for decades although their use is increasing as the technology and and breadth of options increase. It is postulated that CG improves both athletic performance and recovery. CG have been reported to reduce blood lactate accumulation following exercise, reduce muscle oscillation and vibration, maintain repeated vertical jump power, and improve post-exercise clearance of muscle damage markers (Duffield, 2010). Many styles of CGs exist, including stockings (knee length, thigh length), sleeves, upper-body garments (covering the torso and the upper limbs in full or part) and lower-body garments (from the waist, covering the lower limbs in full or part) (MacRae, 2011).

The mechanism by which CG provide benefits to athletic performance and/or aid in recovery is unclear. They may stabilize the soft tissue or joint. Another theory is the compression reduces ‘available space’ for swelling and blood by creating a pressure gradient. Another is enhanced blood flow improving clearance of exercise metabolites. Finally, the decrease in space may decrease cytokine chemotaxis, blunt the the inflammatory response, or some combination of the above.

Compression garments appear to help reduce delayed onset muscle soreness (DOMS). A 2014 meta-analysis of 12 relevant studies found that compression garments had a moderate reduction in the severity of DOMS, muscle damage, muscle power and creatine kinase (CK) (Hill, 2014). In one study involving marathon runners, there was a lower subjective level of muscle soreness, but there was no difference in strength or blood tests (Hill, 2014). Compression reduced perceived muscle soreness, fatigue, and rating of perceived exertion during exercise designed to simulate manual labor (Chan 2016). In athletes performing biceps curls, CG decreased subjects’ perception of soreness and reduced swelling (Kraemer, 2001). Interestingly, a pneumatic compression device, which uses an inflatable cuff, was superior to standard CG for DOMS of the elbow flexors (Winke, 2018).

Compression garments may help with muscle recovery and attenuate loss of power after exercise. CG worn for 24 hours post exercise showed faster recovery in both bench press and knee extensions with reduced circumference of arm and thigh compared to the non-compression arm (Goto, 2014). In sprinters, CG with adhesive strips improved 30m sprint performance (Born, 2014). In eccentric drop jumps, high pressure CG improved maximal voluntary contract, countermovement jump height and jump height at 24 hours post exercise (Hill, 2017). Use of CG during 30 minutes running improved subsequent jump performance (Mizuno, 2016). In athletes performing biceps curls, CG promoted recovery of force production (Kraemer, 2001). In the most recent 2017 meta-analysis, the authors concluded that CG attenuated strength recovery at 2-8 hours and >24 hours, enhanced recovery from resistance training and next day cycling (Brown, 2017).

Compression garments do not appear to help mitigate inflammatory markers after exercise. In  one study, blood tests were similar between groups (Blood lactate, insulin like growth factor-1, free testosterone, myoglobin, creatine kinase, interleukin 6, and interleukin 1) (Goto, 2014). In athletes exercising with and without CG on the lower extremities during and 24 hours following exercise, researchers found an improvement in perceived muscle soreness but no difference on heart rate, rate of perceived exertion, lactate, pH, CK or c-reactive protein (CRP) (Duffeld, 2010).

It is worth noting that not all research on compression garments is favorable. In exercising athletes, ankle CG did not aid in recovery or lactate clearance (Sambaher, 2016). In 2011, a review of CG on recovery found some studies showed improvements on power and torque however these findings were not consistent. They found ratings of post-exercise muscle soreness generally decreased but overall stated that the findings of CG on recovery performance was inconclusive (MacRae, 2011).

One of the challenges in evaluating the efficacy of compression garments is the heterogeneity of products, which body parts they are applied to, variations between brands and which ones are studied. This makes research evaluating them challenging as well as extrapolating data from say a compression garment for the wrist to one for the knee. Keeping that in mind, the majority of studies conclude that compression garments help with DOMS and a sensation of fatigue. There is also a fair number of studies that suggest the use of CG as a recovery tool improves subsequent strength recovery, force production, sprint and jump performance. The majority of evidence does not support the utility of CG in clearing post-exercise blood markers (i.e. lactate, CK, etc). Taken in totality, CG appear to have utility as a recovery aid. The heterogeneous nature of the products and research makes generalization difficult, but there are no known side effects and their likely benefit makes them an easy recommendation to use as a recovery modality. More research is needed to better delineate the best types of compression garments and parts of the body where they are most efficacious.

 
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Heat. Heat therapy, sometimes referred to as thermotherapy, is the application of heat to a body part resulting in increased temperature. Heat therapy is popular among athletes and lay people alike for the treatment of a variety of soft tissue ailments. Heat can come in the form of reusable or disposable hot packs, water bottles, heat pads, electrical heat pads, stones, baths, sauna, paraffin wax, medications, heat lamps and more. Physiological effects of heat therapy include pain relief, increased blood flow, metabolism and elasticity of connective tissue (Nadler, 2004). Adverse events from heat therapy are low. According to a 2006 Cochrane review, adverse events related to use of superficial heat were minor, mainly consisting of “pink skin” (French, 2006).

Mechanisms by which heat improves recovery are unclear. In mouse models, heat improved the rate of glycogen synthesis, the major storage device for glucose consumed during exercise (Cheng, 2017). Heat therapy causes vasodilation and increased blood flow, which is thought to promote healing, supply of nutrients and oxygen to areas of injury, including muscles. Metabolism is increased by heat. Heat appears to have some effect on the visco-elastic properties of connective tissue and has been shown to modulate pain by interacting with P2X2 purine channels.

Heat therapy appears to help with recovery from DOMS and post-exercise related pain. Heat therapy appears to help with pain and promotion of healing, especially with lower back pain (Malanga, 2015). In individuals performing eccentric back extensions, participants who used heat prior to exercise reported nearly 50% reduction in pain intensity, disability and deficits at 24 hours post exercise. In the same study but in a separate arm, individuals who used heat wrap post exercise reported a significant improvement in pain relief compared to cold pack (Mayer, 2006). In a study of Finnish athletes, far infrared heat therapy improved recovery from anaerobic exercise, decreased sensation of muscle soreness compared to passive recovery (Noponen, 2013).

There may also be some recovery benefits for range of motion and post-exercise performance. A 2013 meta-analysis concluded that heat increases ROM and a combination of heat and stretching is more effective than stretching alone (Bleakley, 2013). Mean power output following upper extremity exercise was better maintained with heat (Cheng, 2017). In a study of athletes performing leg squats, heat was superior to control for attenuating loss of strength (24% vs 4%), prevented elastic muscle damage and reducing pain (Petrofsky, 2015). It is worth noting that not all studies find positive results. In a study of college students performing vertical jump and wingate protocol, thermotherapy was equivocal to cryotherapy and passive recovery (Feister, 2017).

One limitation of heat therapy is lack of clear criteria on “how much and how long,” meaning how significant of a temperature increase is needed to facilitate benefit and how long the heating process should last. A few studies have evaluated this, suggesting the largest intramuscular increase in temperature is just 0.4 ℃, while suggesting that some modalities such as deep thermal US can induce changes up to 4 ℃ (Garrett, 2000). There is also a lack of clarity about which modality, if any, is superior. Petrofsky et al reported that chemical moist heat wrap was superior to hydrocollator and air-activity heat wrap for pain reduction following exercise (Petrofsky, 2011). Most studies recommend applied heat for 20-30 minutes at a time.

In summary, heat therapy appears to be a safe recovery modality with some evidence supporting benefits. The mechanism of benefits remains unclear at this point. Thermotherapy appears to help with muscle related pain and sensation of muscle soreness following exercise. Heat appears to help with range of motion, especially in combination with stretching. In recovering athletes, heat may also facilitate maintenance of power output and strength following exercise. It is important to note not all studies find benefit. There is a lack of clarity about how much heat is required and for how long, although most studies recommend 20-30 minutes at a time.

 
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Cold. The use of cold therapy to recover from physical activity is popular among athletes. Various modalities are utilized including cold water immersion (CWI), cold water application, ice packs, cooling vests, cooling rooms or chambers, ice massage and cold drinks. Cold water immersion (CWI) is a popular recovery strategy. It is generally aimed at alleviating post-exercise pain and DOMS.

The mechanism of cold facilitating recovery are poorly understood. Proposed mechanisms of CWI are speculated to be related to temperature- and pressure-induced changes in blood flow, namely vasoconstriction, and reduced muscle temperature per se, subsequently reducing post-exercise inflammation (Leeder, 2012). The decrease inflammation is postulated to decrease cellular metabolism. Several possible beneficial mechanisms of cooling have been suggested, including muscle temperature decrease, reducing muscle damage, as well as post exercise inflammation; reduced heart rate and cardiac output; peripheral vasoconstriction; reduced peripheral edema formation; and analgesic effects (Poppendieck, 2013).

Cold therapy appears to help with post-exercise fatigue, pain and DOMS. One meta-analysis found that CWI was effective at alleviating DOMS for up to 96 hours, the effect was more pronounced in high-intensity interval training than eccentric exercises (Leeder, 2012). Another meta-analysis found similar results, with cooling significantly alleviating DOMS for up to 96 hours and ratings of perceived exertion (Hohenauer, 2015). Cold therapy improved perception of pain following eccentric and concentric knee exercises (Pointon, 2011). In runners, whole body cryotherapy was superior to infrared and passive modalities for recovery from exercise induced muscle damage (Hausswirth, 2011). In one cohort of athletes, CWI enhanced neuromuscular recovery at 24 hours, perceptions of fatigue at 72 hours but not perception of muscle soreness (Higgins, 2017). Among athletes with sports-related soft tissue injuries, application of active cold gel four times daily for 14 days significantly reduced pain scores and patient satisfaction compared to placebo (Airaksinsen, 2003).

It is less clear whether cold therapy helps with performance recovery. Cold therapy as a recovery modality was found to help with sprint performance, with smaller effect sizes seen for jumping and strength (Poppendieck, 2013). In basketball players, CWI after competitive matches lowered perception of fatigue, improved jump performance, without any effect on repeated sprints (Delextrat, 2013). Among rugby players, cold water immersion improved maximal isometric voluntary contraction compared to passive recovery (Pournot, 2010). Pointon et al found cold therapy did not improve MVC following eccentric and concentric knee exercises (Pointon, 2011).

The effect on inflammatory markers is unclear. Ascensao et al found CWI on athletes after a single soccer match had lower creatine kinase (30 min, 24 h, 48 h), myoglobin (30 min), C-reactive protein (30 min, 24 h, 48 h), and improved quadriceps strength (24 h), and quadriceps (24 h), calf (24 h) and adductor (30 min) delayed-onset muscle soreness compared to controls (Ascensao, 2011). In another study of soccer players, cold water immersion reduced perceptions of fatigue but did not induce modifications of inflammatory or hematological markers (De Nardi, 2011). Pournot found reduced leukocytes at 1 hour and plasma CK at 24 hours (Pournot, 2010). One meta-analysis found reduced CK levels (Leeder, 2012), while another found no difference in lactate, CK or IL-6 levels compared to controls (Hohenauer, 2015).

Not all studies demonstrated a benefit. In individuals performing eccentric muscle exercises, application of ice packs delayed recovery after eccentric exercise compared to controls (Tseng, 2013). In sprinters, cold water immersion therapy was superior to passive control in the rate of reduction of core temperature, heart rate and muscle soreness and improved MVC and voluntary activation at 2 hours. However, at 24 hours, the control athletes had better MVC and voluntary activation (Pointon, 2012)

Previous studies have suggested whole body cooling does not appear to be harmful or have any negative effects in athletes. Temperature goals vary widely across most studies from 5 ℃ to 15 ℃, although a few reached temperatures below 0 ℃ (Hohenauer, 2015). One study found a dose-response relationship between temperature and alleviation of DOMS, with the greatest benefit from water temperature of 11-15 ℃ with an immersion time of 11 - 15 minutes (Machado, 2016). It is unclear what cooling modality, if any, is superior. Poppendieck et al found CWI and cryotherapy to be superior to cooling packs for performance recovery (Poppendieck, 2013). Additionally, they found whole body immersion to be superior to just immersing arms or legs.

In summary, the research on cold therapy as a recovery modality for athletes is challenging to interpret. Most studies, but not all, suggest that cold therapy helps with DOMS, post-exercise fatigue and pain. The effects on performance are mixed, with some suggesting benefits and others not. Although intuitively cold therapy should lower post-exercise inflammatory markers and markers of muscle damage, not all studies resulted in this conclusion. The superiority of one cold modality over another remains unclear, although most research uses cold water immersion. The temperature and duration of benefit are not well established, but the best study recommends 11-15 ℃ with an immersion time of 11 - 15 minutes. Cold therapy should be recommended to help with post-exercise muscle soreness and fatigue but approached with caution when discussing the effects on performance.

Heat vs Cold. One of the most commonly asked questions among patients is: heat, cold or both? Which is superior? There is controversy regarding the effectiveness of cold and heat after exercise. This common clinical conundrum is clouded by personal experience and bias, patient experience, the opinion of athletic trainers, and the lack of clear evidence in the medical literature. This is further complicated by the lack of clarity in the literature evaluating individual heat and cold therapies. There is also lack of consensus which modality of application is best, duration of application, temperature treatment goals, which forms of exercise benefit and which areas of the body have the greatest benefit. Cold is better tolerated at extreme temperatures, allowing for more rapid cooling than heating pads, which require more time for warming the muscles to avoid warming too quickly and burning the skin.

A few studies have tried to compare heat and cold. A 2006 Cochrane review evaluating heat or cold for low back pain generally concluded that the quality of evidence was low for both. They did state that heat wrap therapy provides short-term reduction in acute and subacute back pain and that no conclusions could be drawn about the use of cold for low back pain (French, 2006). More recently, Malanga concluded that there was some clinical evidence that cold therapy is effective for pain relief of acute musculoskeletal injuries, but more high powered, high quality studies are required. They also concluded that heat therapy has better demonstrated therapeutic benefit for both analgesic and promoting healing (Malanga, 2015). They concluded that heat was the modality of choice for acute low back pain and muscle soreness.

The best and most recent study was was done by Petrofsky et al. They had 100 athletes, age 20-29, perform leg squats and then use either heat or ice for the subsequent 24 hours (Petrofsky, 2015). Both modalities were effective in reducing muscle damage and pain. Cold was a superior analgesic both immediately after exercise and at 24 hours. Heat applied immediately after exercise was best for attenuating loss of strength and muscle damage as measured by serum myoglobin. At 24 hours, cold was superior to heat in reducing tissue damage and attenuating strength loss.

Conclusion. In conclusion, we can safely say compression garments help with DOMS and sensation of fatigue and may also help as a recovery tool for performance. The challenge with compression garments will be clarifying the best types of compression garments and parts of the body where they are most efficacious. Heat therapy is a safe recovery modality that helps with muscle related pain and soreness, range of motion and may help with performance. Cold therapy helps with DOMS and post-exercise fatigue; the evidence is mixed on performance recovery.

It is difficult to provide evidence based recommendations regarding the superiority of heat vs cold as a recovery modality following exercise. Based on the petrofsky study, which provides the best data available, cold is a superior analgesic to heat. For attenuating muscle damage and strength loss, heat was superior for the first 24 hours, after which cold was superior. Ultimately, there remains an ongoing need for more sufficiently powered high-quality RCTs on the effects of cold and heat therapy on recovery after exercise. One of the challenges is creating blinded studies of cold and heat. The majority of studies are non-blinded which subjects them to bias. Additionally, when recommending heat or cold therapies, there is a lack of clarity of “how much and for how long”. Researchers also need to delineate which modalities of heat and cold application are superior.


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