The effect of graduated compression socks on calf muscle oxygenation of endurance athletes

[摘要] ENGLISH ABSTRACT: Compression socks (CS) are used as an ergogenic aid during and after exercise by many athletesof elite and recreational status. The exact mechanism whereby CS affect performance and postexerciserecovery is not yet elucidated. Some research ascribes the beneficial effects to improvedlactate removal rates with CS. One hypothesis is that CS improve venous return and therebyremove the lactate from the tissue to other tissues such as the liver, and the second hypothesis isthat the CS cause retention of the lactate within the muscle and therefore improve the oxidation ofthe lactate within the muscle (Berry & McMurray, 1987).The current study endeavoured to test the hypothesis set by Berry and McMurray (1987) bymeasuring the effect of CS as well as flight socks (FS) on muscle oxygenation during exercise andrecovery in endurance trained runners and triathletes.Eleven male endurance trained runners and triathletes (age = 34.8 ± 3.8 years, VO2max = 52.4 ± 7.1mL.kg-1.min-1) participated in the study. They completed an incremental exercise test to exhaustionto determine their maximal aerobic capacity (VO2max) and peak treadmill velocity (PTV). Then theycompleted two 10 km treadmill running tests at 80 % of their PTV. During these two trialsparticipants wore either CS or FS; the order of treatment was randomly selected. A subset of thestudy sample (n = 5) also completed a control test wearing only their ankle length sport socks(NS). After these trials, participants completed a 60 minute passive recovery period in the seatedposition while muscle oxygenation was measured.Compression under the socks was measured at several anatomically determined measurementpoints prior to the commencement of the exercise test, along with the determination of bloodhaemoglobin concentration ([Hb]). During the exercise trials, blood lactate concentration ([BLa]),skin temperature (ST),oxygen consumption (VO2), carbon dioxide production (VCO2), heart rate(HR), and muscle oxygenation variables (oxy-haemoglobin (O2Hb), deoxy-haemoglobin (HHb),tissue oxygenation index (TOI) and total haemoglobin index (nTHI)) was measured . During the 60minute passive recovery period, [BLa], ST, O2Hb, HHb, TOI, and nTHI measurements werecontinued.The results showed that there were differences in the pressure exerted between the two pressurecondition (CS and FS) at the posterior ankle, and under the elastic of the sock as well as on theanterior calf at the level of greatest calf circumference. Differences in ST between the CS and NSand the FS and NS conditions were found between the first four 2 km intervals of the exerciseprotocol, but not during recovery.No differences were found in [BLa] between the three different compression conditions duringeither the exercise (p = 0.19) or recovery period (p = 0.63), as well as no differences in thecardiorespiratory variables during exercise between the three different compression conditions(VO2, p = 0.06; VCO2, p = 0.12; HR, p = 0.36). With regard to the muscle oxygenation variables, nodifferences were found between the three compression conditions during exercise, however therewas a trend for lower oxygen utilization (HHb) during exercise in the NS condition (p = 0.57,medium to large practical significance). There were also no differences in these variables (O2Hb, p= 0.65; HHb, p = 0.57; TOI, p = 0.39; nTHI, p = 0.22) during recovery, although oxygen utilization(HHb) showed a faster recovery rate with increasing external pressure.From the results obtained, it seems that external compression caused a decrease in the blood flowvelocity within the muscle, thereby increasing oxygen diffusion rate. During exercise this did notfacilitate differences in [BLa], however, after the first 10 minutes of the recovery period, largepractical differences were found between the NS and both sock conditions, suggesting that theincrease in oxygen diffusion improved lactate clearance. This could support the hypothesis set byBerry and McMurray (1987).

[发布机构] Stellenbosch University