compression therapy is used for the treatment of venous pathologies such as deep vein thrombosis and chronic - venous insufficiency .
the application of the external pressure on the lower limbs acts to compress the veins thus reducing their diameter . in consequence
the velocity increases , which in turn encourages the return of blood to the heart and reduces pooling .
many studies have demonstrated an increase in mean deep venous velocity , reduced venous pooling , and an improved venous return in patients who wore graduated compression stockings [ 35 ] .
the use of compression garments in sport is becoming increasingly popular due to claims that they can improve recovery from exercise , by exerting these hemodynamic effects .
evidence for the efficacy of compression garments in recovery is solid with recent meta - analysis supporting the use of compression to alleviate symptoms associated with fatigue [ 6 , 7 ] .
suggested mechanisms include enhanced venous return and blood flow in passive conditions [ 8 , 9 ] that may aid the removal of metabolic waste [ 10 , 11 ] , reduce edema [ 12 , 13 ] , and improve muscle oxygenation [ 14 , 15 ] .
however in some cases there is little evidence to support some of the purported benefits and gaps in knowledge are still evident [ 16 , 17 ] .
the heterogeneity of effects could be explained by the disparity in terms of compression garments in all studies [ 6 , 7 ] .
for example , findings of french et al .   indicate that recovery and regeneration appear unaffected by wearing compression garments for 12  h after a hard training session compared with passive recovery .
however , it should be clearly stated that one limitation of this study is that compression garments used were reported to have an average compression pressure of 12  mmhg at the calf .
indeed venous return and other hemodynamic benefits which may aid recovery were previously described to be significantly improved with a minimum compression pressure of 1520  mmhg and with a peak for a pressure of around 40  mmhg [ 2 , 18 ] .
some other studies present such limitation [ 19 , 20 ] and recent meta - analysis suggest understanding the discrepancy of results well to focus on the characteristics of compression garments especially compression pressure [ 6 , 7 ] .
therefore the aim of the present study was to assess the changes in tissue oxygen saturation ( sto2 ) in response to the application of the main commercially available calf compression sleeves .
we focused on sto2 because it has been extensively documented as a hemodynamic benefit of compression garments during recovery .
it also presents the advantage of being noninvasively measured using near - infrared spectroscopy ( nirs ) .
eight healthy subjects ( no history of cardiopulmonary disease or medication ) were studied ( mean  sd : age , 32.4  4.8 years ; height , 174.5  1.9  cm ; body mass , 66.1  2.2  kg ; calf circumference at larger part : 36.4  0.2  cm ) .
they were informed about the procedures and risks associated with participation in the study and all provided their written informed consent prior to participation .
the study protocol was approved by the local ethics committee and was in accordance with the declaration of helsinki of the world medical association with regard to research conduct .
the subjects came to the laboratory ( temperature : 20.0  1.0c ; humidity : 50  1.0% ) to complete a session in seated position including 10  min of quiet rest followed by 3  min measuring calf sto2 without compression sleeves and then alternating of 3  min of quiet rest and 3  min measuring sto2 with calf compression sleeves .
a total of 15 different commercially available compression sleeves were studied in a randomized order ( figure 1 ) . using nirs technique , the inspectra sto2 tissue oxygenation monitor , model 650 ( hutchinson , mn , usa ) , provides continuous noninvasive assessment of sto2 at a maximum depth of 15  mm .
the measurement principles of this technology have been described   and its accuracy and reproducibility have been previously established .
the microcirculatory sto2 assessment is defined as the ratio [ hbo2]/([hb]+[hbo2 ] ) expressed as percent , with hbo2 and hb being oxy- and deoxygenated hemoglobin , respectively .
sto2 was measured at the level of the right gastrocnemius muscle , 12  cm below the fibula head .
a transparent film was placed between the skin and the probe to protect it from sweat .
sto2 was measured during three minutes without compression and during three minutes with each calf compression sleeve .
sto2 values were analyzed with sto2 researcher 's analysis software version 4 ( hutchinson , mn , usa ) .
only the mean of the last minute of each 3  min period was considered .
the pressure of each calf sleeve was measured at the same area as the sto2 measurement using a pneumatic measuring system ( picopress , microlabitalia , padua , italy ) .
the pressure transducer consists of a flat plastic pressure probe ( 5  cm diameter ) that is filled with 2  ml of air for the pressure measurement .
fluctuations of pressure on this probe are transformed into electronic signals that can be recorded continuously .
data are presented as mean  sd . a p value < 0.05 was considered as significant .
the normality of distribution was tested using the kolmogorov - smirnov test . to assess the effects of the calf compression sleeves ,
sto2 was significantly increased with all compression sleeves ( p < 0.05 ) compared with no compression ( from + 6.9% for a to + 22.6% for o ) .
sto2 was positively correlated with compression pressure ( p < 0.05 ; r = 0.84 ) .
the present study aimed at investigating the changes in sto2 in response to the application of the main commercially available calf compression sleeves .
( 1 ) wearing all compression sleeves significantly increased sto2 and ( 2 ) the most effective increases of sto2 were correlated with the highest compression pressures .
firstly , sto2 increased with calf compression sleeves ( from + 6.9% for a to + 22.6% for o ) .
these results are in accordance with previous works that reported an increase in sto2 with calf compression sleeves before and after running   or cycling exercises .
this higher sto2 was attributed to the increased muscle flow rate [ 8 , 9 ] and changes in skin blood flow [ 26 , 27 ] . indeed , wearing compression on the lower limbs
venous emptying may increase arteriovenous pressure gradient , increasing arterial flow rate , oxygen supply , and therefore sto2 .
as previously described , arterial vessels dilate in response to a fall of the transmural vessel pressure gradient . the pressure applied by sleeves
is transmitted into the tissue and thus reduces the transmural pressure gradient of the arterial vessels .
finally , changes in skin blood flow must also be considered [ 26 , 27 ] .
indeed , sto2 was recorded at a maximum depth of 15  mm , including cutaneous and muscular vessels . moreover ,
previous studies suggest that compression sleeves may affect cutaneous sto2 through temperature changes [ 14 , 27 ] and pressure - induced skin vasodilation [ 26 , 30 ] .
this study also revealed that increase of calf sto2 with compression sleeves was positively correlated with compression pressure ( p < 0.05 ; r = 0.84 ) .
this finding is in agreement with previous studies suggesting a dose - response of compression pressure on venous hemodynamics including the velocity of venous circulation , venous pump function , or the degree of decrease in edema [ 2 , 3 , 31 ] .
however , the relation between the compression pressure and its effects on hemodynamics is not systematically demonstrated [ 3133 ] .
a possible explanation for this lack of relation is that hemodynamics may also be affected by other factors such as pressure gradient [ 24 , 32 ] and elastic properties [ 34 , 35 ] .
for example , it has been shown that with the same pressure inelastic material is more effective than elastic [ 34 , 35 ] . by extension
the seamless knitting could be in favor of long lasting effects on sto2 : no fraying and stitch defects making the sleeves loose fit and negatively affecting compression and elastic properties .
this study provides support for the hypothesis that wearing compression sleeves from various brands may differently affect recovery , by virtue of their varied effects on sto2 .
these results contribute to understanding well the large differences reported in recent meta - analysis [ 6 , 7 ] about effects of compression garments during recovery .
since higher compression pressure was associated with higher sto2 this work suggests focusing on compression garments with high pressure level for recovery .
in conclusion , this study shows that wearing compression sleeves from various brands differently increases tissue oxygen saturation .
differences were linked to the compression pressure : higher compression pressures were associated with higher sto2 .
 
 aim . the purpose was to examine the changes in tissue oxygen saturation ( sto2 ) in response to the application of different commercially available calf compression sleeves . 
 methods . 
 eight subjects came to the laboratory to complete a session in seated position including 10  min of quiet rest followed by 3  min measuring calf sto2 without compression sleeves and then alternating of 3  min of passive rest and 3  min measuring sto2 with calf compression sleeves . 
 a total of 15 different commercially available compression sleeves were studied in a randomized order . 
 calf sto2 was recorded using near - infrared spectroscopy . 
 results . 
 sto2 was significantly increased with all compression sleeves ( p < 0.05 ) compared with no compression ( from + 6.9% for the least effective to + 22.6% for the most effective ) . 
 large differences were observed between compression sleeves ( p < 0.05 ) . 
 sto2 was positively correlated with compression pressure ( p < 0.05 ; r = 0.84 ) . 
 conclusion . 
 this study shows that wearing compression sleeves from various brands differently affects tissue oxygen saturation . 
 differences were linked to the compression pressure : higher compression pressures were associated with higher sto2 . 
1. Introduction
2. Materials and Methods
3. Results
4. Discussion
5. Conclusions