***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Prior peripheral hypoxia induced via remote ischemic preconditioning ( IPC ) can improve physical performance in male athletes through improved O2 delivery and utilization . Since females may have an innate protective mechanism against ischemia-reperfusion injury , and since muscle metabolism during contraction differs between sexes , it is relevant to examine the impact of sex in response to IPC to determine whether it is also ergogenic in females . In a r and omized , crossover , single-blind study , we investigated muscle performance , hemodynamic and O2 uptake in strength-trained males ( n = 9 ) and females ( n = 8) performing five sets of 5 maximum voluntary knee extensions on an isokinetic dynamometer , preceded by either IPC ( 3 × 5-min ischemia/5-min reperfusion cycles at 200 mmHg ) or SHAM ( 20 mmHg ) . Changes in deoxy-hemoglobin ( Δ[HHb ] , expressed in percentage of arterial occlusion and considered an index of O2 extraction ) , and total hemoglobin ( Δ[THb ] ) concentrations of the vastus lateralis muscle were continuously monitored by near-infrared spectroscopy . The metabolic efficiency of the contractions was calculated as the average force/Δ[HHb]avg ratio . Cohen 's effect sizes ( ES ) ± 90 % confidence limits were used to estimate IPC-induced changes and sex differences . IPC increased total muscular force in males only ( 13.0 % , ES 0.64 , 0.37;0.90 ) , and this change was greater than in females ( 10.4 % difference , ES 0.40 , 0.10;0.70 ) . Percent force decrement was only attenuated in females ( −19.8 % , ES −0.38 , −0.77;0.01 ) , which was clearly different than males ( sex difference : ES 0.45 , −0.16;1.07 ) . IPC also induced different changes between sexes for average muscle O2 uptake in set 2 ( males : 6.4 % vs. females : −16.7 % , ES 0.21 , −0.18;0.60 ) , set 3 ( males : 7.0 % vs. females : −44.4 % , ES 0.56 , −0.17;1.29 ) , set 4 ( males : 9.1 % vs. females : −40.2 % , ES 0.51 , −0.10;1.13 ) , and set 5 ( males : 10.2 % vs. females : −40.4 % , ES 0.52 , −0.04;1.09 ) . However , metabolic efficiency was not meaningfully different between conditions and sexes . IPC  increased muscle blood volume ( ↑[THb ] ) at rest and during recovery between sets , to the same extent in both sexes . Despite a similar IPC-induced initial increase in O2 delivery in both sexes , males displayed greater peripheral O2 extraction and greater strength enhancement . This ergogenic effect appears to be mediated in part via an up regulated oxidative function in males . We conclude that strength-trained males might benefit more from IPC than their female counterparts during repeated , maximal efforts Background Coaches continually seek new ways of doing things and also refine existing techniques to improve sporting performance . Coaches are currently experimenting using ischaemic preconditioning ( IPC ) over consecutive days in the hope of improving competitive performances . Aims First , to quantify the physiological impact of 1 week of IPC on simulated Keirin cycling performance . Second , to investigate if biochemical stress markers are affected over the treatment period . Methods Using a r and omised , sham-controlled design , 18 active adults undertook seven consecutive days of IPC treatment ( 4 × 5 min occlusion/reperfusion ) applied to each leg at either 220 mm Hg ( treatment , n=9 ) or 20 mm Hg ( sham , n=9 ) . Urinary measures of inflammation , oxidative stress and indirect nitric oxide synthesis were undertaken daily . A simulated Keirin cycling competition ( 4 × 30 s Wingate tests ) was performed on day 10 , with baseline and postintervention cycling VO2max ( days 1 , 11 and 18 ) and 30 s Wingate tests ( day 2 ) undertaken for comparison . Results The treatment group had enhanced mean cycling power ( 3.4 % ) , while neopterin and biopterin in conjunction with total neopterin were significantly lower ( p<0.05 ) and total biopterin significantly greater ( p<0.05 ) during the simulated Keirin . Aerobic fitness measures significantly improved from baseline to postintervention ( VO2peak : 12.8 % ↑ , maximal aerobic power : 18.5 % ↑ ) . Conclusions Seven consecutive days of IPC improved aerobic and anaerobic capacity measures , with modulations in oxidative stress , immune system activation and nitric oxide/catecholamine synthesis This study investigated the effects of ischemic preconditioning ( IPC ) on the ratings of perceived exertion ( RPE ) , surface electromyography , and pulmonary oxygen uptake ( V̇o2 ) onset kinetics during cycling until exhaustion at the peak power output attained during an incremental test . A group of 12 recreationally trained cyclists volunteered for this study . After determination of peak power output during an incremental test , they were r and omly subjected on different days to a performance protocol preceded by intermittent bilateral cuff pressure inflation to 220 mmHg ( IPC ) or 20 mmHg ( control ) . To increase data reliability , the performance visits were replicated , also in a r and om manner . There was an 8.0 % improvement in performance  after IPC ( control : 303 s , IPC 327 s , factor SDs of ×/÷1.13 , P = 0.01 ) . This change was followed by a 2.9 % increase in peak V̇o2 ( control : 3.95 l/min , IPC : 4.06 l/min , factor SDs of ×/÷1.15 , P = 0.04 ) , owing to a higher amplitude of the slow component of the V̇o2 kinetics ( control : 0.45 l/min , IPC : 0.63 l/min , factor SDs of ×/÷2.21 , P = 0.05 ) . There was also an attenuation in the rate of increase in RPE ( P = 0.01 ) and a progressive increase in the myoelectrical activity of the vastus lateralis muscle ( P = 0.04 ) . Furthermore , the changes in peak V̇o2 ( r = 0.73 , P = 0.007 ) and the amplitude of the slow component ( r = 0.79 , P = 0.002 ) largely correlated with performance improvement . These findings provide a link between improved aerobic metabolism and enhanced severe-intensity cycling performance  after IPC . Furthermore , the delayed exhaustion after IPC under lower RPE and higher skeletal muscle activation suggest they have a role on the ergogenic effects of IPC on endurance performance Purpose Endurance athletes often compete and train at altitude where exercise capacity is reduced . Investigating acclimation strategies is therefore critical . Ischemic preconditioning ( IPC ) can improve endurance performance at sea level through improved O2 delivery and utilization , which could also prove beneficial at altitude . However , data are scarce , and there is no study at altitudes commonly visited by endurance athletes . Methods In a r and omized , crossover study , we investigated performance and physiological responses in 13 male endurance cyclists during four 5-km cycling time trials ( TT ) , preceded by either IPC ( 3 × 5 min ischemia/5-min reperfusion cycles at 220 mm Hg ) or SHAM ( 20 mm Hg ) administered to both thighs , at simulated low ( FIO2 0.180 , ~1200 m ) and moderate ( FIO2 0.154 , ~2400 m ) altitudes . Time to completion , power output , cardiac output ( Q˙ ) , arterial O2 saturation ( SpO2 ) , quadriceps tissue saturation index ( TSI ) and RPE were recorded throughout the TT . Differences between IPC and SHAM were analyzed at every altitude using Cohen effect size ( ES ) and compared with the smallest worthwhile change . Results At low altitude , IPC possibly improved time to complete the TT ( −5.2 s , −1.1 % ; Cohen ES ± 90 % confidence limits −0.22 , −0.44 ; 0.01 ) , power output ( 2.7 % ; ES 0.21 , 0.08 ; 0.51 ) , and Q˙ ( 5.0 % ; ES 0.27 , 0.00 ; 0.54 ) , but did not alter SpO2 , muscle TSI , and RPE . At moderate altitude , IPC  likely enhanced completion time ( −7.3 s ; −1.5 % ; ES −0.38 , −0.55 ; −0.20 ) , and power output in the second half of the TT ( 4.6 % ; ES 0.28 , −0.15 ; 0.72 ) , increased SpO2 ( 1.0 % ; ES 0.38 , −0.05 ; 0.81 ) , and decreased TSI ( −6.5 % ; ES −0.27 , −0.73 ; 0.20 ) and RPE ( −5.4 % , ES −0.27 , −0.48 ; −0.06 ) . Conclusions Ischemic preconditioning may provide an immediate and effective strategy to defend SpO2 and enhance high-intensity endurance performance at moderate altitude Purpose Recent studies have reported ischemic preconditioning ( IPC ) can acutely improve endurance exercise performance  in athletes . However , placebo and nocebo effects have not been sufficiently controlled , and the effect on aerobic metabolism parameters that determine endurance performance ( e.g. , oxygen cost of running , lactate threshold , and maximal oxygen uptake [ V˙O2max ] ) has been equivocal . Thus , we circumvented limitations from previous studies to test the effect of IPC on aerobic metabolism parameters and endurance performance in well-trained runners . Methods Eighteen runners ( 14 men/4 women ) were su bmi tted to three interventions , in r and om order : IPC ; sham intervention ( SHAM ) ; and resting control ( CT ) . Subjects were told both IPC and SHAM would improve performance compared to CT ( i.e. , similar placebo induction ) , and IPC would be harmless despite circulatory occlusion sensations ( i.e. , nocebo avoidance ) . Next , pulmonary ventilation and gas exchange , blood lactate concentration , and perceived effort were measured during a discontinuous incremental test on a treadmill . Then , a supramaximal test was used to verify the V˙O2max and assess endurance performance ( i.e. , time to exhaustion ) . Results Ventilation , oxygen uptake , carbon dioxide output , lactate concentration , and perceived effort were similar among IPC , SHAM , and CT throughout the discontinuous incremental test ( P > 0.05 ) . Oxygen cost of running , lactate threshold , and V˙O2max were also similar among interventions ( P > 0.05 ) . Time to exhaustion was longer after IPC ( mean ± SEM , 165.34 ± 12.34 s ) and SHAM ( 164.38 ± 11.71 s ) than CT ( 143.98 ± 12.09 s ; P = 0.02 and 0.03 , respectively ) , but similar between IPC and SHAM ( P = 1.00 ) . Conclusions IPC did not change aerobic metabolism parameters , whereas improved endurance performance . The IPC improvement , however , did not surpass the effect of a placebo intervention Exposure to hypoxic environments is associated with decreased arterial oxygen saturation and increased pulmonary artery pressures .  Ischemic preconditioning of an extremity ( IPC ) is a procedure that stimulates vasoactive and inflammatory pathways that protect remote organ systems from ongoing or future ischemic injury . To test the effects of IPC on oxygen saturation and pulmonary artery pressures at high altitude , 12 healthy adult volunteers were evaluated in a r and omized cross-over trial . IPC was administered utilizing a st and ardized protocol . IPC or placebo was administered daily for 5 days prior to ascent to altitude . All participants were evaluated twice at 4342 m altitude ( placebo and IPC conditions separated by 4 weeks , r and omized ) . The pulmonary artery systolic pressure ( PASP ) at 4342 m was significantly lower in the IPC condition than the placebo condition ( 36 ± 6.0 mmHg vs. 38.1 ± 7.6 mmHg , respectively , p = 0.035 ) . Oxygen saturation at 4342 m was significantly higher with IPC compared to placebo ( 80.3 ± 8.7 % vs. 75.3 ± 9.6 % , respectively , p = 0.003 ) . Prophylactic IPC treatment is associated with improved oxygen saturation and attenuation of the normal hypoxic increase in pulmonary artery pressures following ascent to high altitude Background One or more brief episodes of coronary artery occlusion protect or “ precondition ” the myocardium perfused by that artery from a subsequent episode of sustained ischemia . We sought to determine whether ischemic preconditioning protects only those myocytes subjected to brief coron 
    Output:
    
Most studied showed that IPC intervention can be beneficial to exercise performance .