Increased Skin and Muscle Temperature
Repeated and continual rubbing of the skin causes friction, resulting in increased skin temperature (9) and a proposed increase in blood flow, otherwise known as hyperaemia. There is supporting evidence that effleurage can increase skin and intramuscular temperature as deep as 2.5cm, but muscle temperatures deeper than 2.5cm were not affected (10). Another study also reported that effleurage resulted in an increase in skin temperature, but this quickly returned to baseline after just 10 minutes (9). This suggests that massage, particularly effleurage, may have a very little effect on intramuscular temperatures.
Increased Blood Flow
Various studies have been conducted on the effects of massage on localised blood flow and shown positive effects (increased blood flow) (4, 11-14), however, these studies severely lack authority due to their poor quality – that being, small sample sizes (11, 14, 4) and no reported statistical analysis (11 -14, 4). Other, more robust, studies have found no increase in blood flow following a massage intervention (15, 16). However, they did not measure microcirculation in the muscle which may have been affected. Another study even showed that post-exercise impaired muscle blood flow (17). All this indicates that massage may have little effect on localised blood flow to the muscle, and has not been explored in enough detail.
Asides its influences on blood flow, one recent study has shown that post-exercise massage may be capable of improving blood vessel function after exercise (18), but this yet again warrants the need for more research.
Blood Lactate Removal
Blood lactate is often used as a measure of fatigue and recovery (19-22). Numerous studies have investigated the effects of massage on blood lactate removal (19, 21-24), with only two reporting any sign of increased removal (20, 24). Contrary, another study found that massage actually impairs the removal of lactic acid from within the muscle after exercise (18). The little quantity of supporting evidence, therefore, questions the ability of massage to promote blood lactate removal.
Massage therapy has been shown to cause changes in hormonal levels (cortisol and serotonin) in dance students (25), patients with low back pain (26), depressed adolescent mothers (27), and HIV positive patients (28). Following the massage intervention, the dancers reported a reduction in anxiety (nervousness) and improved mood (25). Despite some research showing reductions in cortisol levels after massage treatment, a 2011 meta-analysis concluded that massage has no effect on cortisol concentrations (29). Whilst the mechanisms responsible for some hormonal changes (i.e. serotonin) are still unclear, a decrease in pre-competition nervousness/anxiety may be beneficial for sports performance (30).