human
***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: In older humans , infusions of endothelial agonists suggest endothelial dysfunction , due in part to less nitric oxide (NO)- and prostagl and in (PG)-mediated vasodilatation , and a shift toward PG-mediated vasoconstriction . Ageing can also be associated with lower exercise blood flow ( exercise hyperaemia ) , but the vascular mechanisms mediating this remain unknown . Notably , in young adults , inhibition of NO and PGs during exercise decreases exercise hyperaemia by approximately 20 and approximately 12 % , respectively . We tested our first hypothesis that in older humans inhibition of NO would decrease hyperaemia , but that inhibition of PGs would increase hyperaemia by blocking vasoconstrictor PGs . Fifteen older subjects ( 65 + /- 3 years ) performed dynamic forearm exercise for 20 min ( 20 contractions min(-1 ) ) . Forearm blood flow ( FBF ) was measured beat-to-beat with Doppler ultrasound , while saline or drugs were infused sequentially via brachial artery catheter in the exercising forearm . After achieving steady-state exercise , L-NAME ( 25 mg ) was infused over 5 min to inhibit NO synthase . After a further 2 min of exercise ( saline ) , ketorolac ( 6 mg ) was infused over 5 min to inhibit PGs , followed by a further 3 min of exercise with saline . Drug order was reversed in seven subjects . L-NAME reduced steady-state exercise hyperaemia by 12 + /- 3 % in older subjects ( P<0.01 ) , whereas ketorolac had no net effect on blood flow ( 3 + /- 6 % , P>0.4 ) . The effects of l-NAME and ketorolac were independent of drug order . By comparing these results with our previous results in young adults , we tested our second hypothesis that in older humans inhibition of NO or PGs would have less impact on exercise hyperaemia due to less vasodilatation from these signals . Our results suggest that , compared with young adults , in older humans the relative contribution of NO to exercise hyperaemia is reduced approximately 45 % ( 22 + /- 4 versus 12 + /- 3 % ) , but the role of PG in mediating vasodilatation is lost in ageing human skeletal muscle . Lower exercise hyperaemia in older humans may be mediated in part by less NO- and PG-mediated vasodilatation during exercise The objectives of this study were to examine the effects of opioid administration on the acute cardiorespiratory and muscle oxygenation responses during a repetitive lifting and lowering test ( RLL ) to voluntary fatigue in participants with chronic low back pain ( LBP ) . Written informed consent was obtained from 27 LBP participants ( mean age 50.9 ± 16.4 years ) who completed one testing session during which they were administered a saline placebo and opioid ( 1 μg/kg of fentanyl intravenously ) in r and om order . The participants performed the RLL at a rate that they felt that they could sustain for an 8-h working day . Acute opioid administration increased the total lifting time and total work done during RLL by 35 and 48 % , respectively ( p < 0.05 ) . However , the increased work capacity was accompanied by a significant ( p < 0.05 ) increase in oxygen cost of 22 % per unit amount of work done and significant ( p < 0.05 ) increases in heart rate ( 7 % ) and ventilation rate ( 10 % ) . Near infrared spectroscopic analysis of erector spinae oxygenation and blood volume responses during RLL indicated no significant ( p > 0.05 ) differences between the opioid and placebo phases . These findings suggest that the increased energy cost of lifting as a result of opioid administration was due to enhanced central oxygen transport and not peripheral muscle oxygen extraction BACKGROUND Aging is associated with increased cardiovascular risk and endothelial dysfunction . Since exercise can improve endothelium-dependent vasodilation , in the present study we tested whether long-term physical activity could prevent aging-related endothelial dysfunction . METHODS AND RESULTS In 12 young and elderly ( age 26.9+/-2.3 and 62.9+/-5.8 years , respectively ) healthy sedentary subjects and 11 young and 14 elderly matched athletes ( age 27.5+/-1.9 and 66.4+/-6.1 years , respectively ) , we studied ( with strain-gauge plethysmography ) forearm blood flow modifications induced by intrabrachial acetylcholine ( 0.15 , 0.45 , 1.5 , 4.5 , and 15 microg/100 mL per minute ) , an endothelium-dependent vasodilator , at baseline , during infusion of N(G)-monomethyl-L-arginine ( L-NMMA ) ( 100 microg/100 mL forearm tissue per minute ) , a nitric oxide-synthase inhibitor , vitamin C ( 8 mg/100 mL forearm tissue per minute ) , an antioxidant , and finally under simultaneous infusion of L-NMMA and vitamin C. The response to  sodium nitroprusside ( 1 , 2 , and 4 microg/100 mL forearm tissue per minute ) was also evaluated . In young athletes and sedentary subgroups , vasodilation to acetylcholine was inhibited by L-NMMA and was not changed by vitamin C. In elderly subjects , vasodilation to acetylcholine was blunted as compared with young subjects in both control subjects and athletes , whereas the response to sodium nitroprusside was similar . Moreover , in elderly athletes , vitamin C did not change the vasodilation to acetylcholine . In contrast , in elderly sedentary subjects , the response to acetylcholine was resistant to L-NMMA . In this subgroup , vitamin C increased the vasodilation to acetylcholine and restored the inhibiting effect of L-NMMA . CONCLUSIONS These results suggest that regular physical activity can at least in part prevent the age-induced endothelial dysfunction , probably the restoration of nitric oxide availability consequent to prevention of production of oxidative stress This systematic review examines the effectiveness of current exercise interventions for the management of frailty . Eight electronic data bases were search ed for r and omized controlled trials that identified their participants as “ frail ” either in the title , abstract , and /or text and included exercise as an independent component of the intervention . Three of the 47 included studies utilized a vali date d definition of frailty to categorize participants . Emerging evidence suggests that exercise  has a positive impact on some physical determinants and on all functional ability outcomes reported in this systematic review . Exercise programs that optimize the health of frail older adults seem to be different from those recommended for healthy older adults . There was a paucity of evidence to characterize the most beneficial exercise program for this population . However , multicomponent training interventions , of long duration ( ≥5 months ) , performed three times per week , for 30–45 minutes per session , generally had superior outcomes than other exercise programs . In conclusion , structured exercise training seems to have a positive impact on frail older adults and may be used for the management of frailty This r and omized trial proposed to determine if there were differences in calf muscle StO2 parameters in patients before and after 12 weeks of a traditional walking or walking-with-poles exercise program .  Data were collected on 85 patients who were r and omized to a traditional walking program ( n = 40 ) or walking-with-poles program ( n = 45 ) of exercise training .  Patients walked for 3 times weekly for 12 weeks . Seventy-one patients completed both the baseline and the 12-week follow-up progressive treadmill tests ( n = 36 traditional walking and n = 35 walking-with-poles ) . Using the near-infrared spectroscopy measures , StO2 was measured prior to , during , and after exercise . At baseline , calf muscle oxygenation decreased from 56 ± 17 % prior to the treadmill test to 16 ± 18 % at peak exercise . The time elapsed prior to reaching nadir StO2 values increased more in the traditional walking group when compared to the walking-with-poles group . Likewise , absolute walking time increased more in the traditional walking group than in the walking-with-poles  group . Tissue oxygenation decline during treadmill testing was less for patients assigned to a 12-week traditional walking program when compared to those assigned to a 12-week walking-with-poles program . In conclusion , the 12-week traditional walking program was superior to walking-with-poles in improving tissue deoxygenation in patients with PAD BACKGROUND AND PURPOSE Assessment of the quality of r and omized controlled trials ( RCTs ) is common practice in systematic review s. However , the reliability of data obtained with most quality assessment scales has not been established . This report describes 2 studies design ed to investigate the reliability of data obtained with the Physiotherapy Evidence Data base ( PEDro ) scale developed to rate the quality of RCTs evaluating physical therapist interventions . METHOD In the first study , 11 raters independently rated 25 RCTs r and omly selected from the PEDro data base . In the second study , 2 raters rated 120 RCTs r and omly selected from the PEDro data base , and disagreements were resolved by a third rater ; this generated a set of individual rater and consensus ratings . The process was repeated by independent raters to create a second set of individual and consensus ratings . Reliability of ratings of PEDro scale items was calculated using multirater kappas , and reliability of the total ( summed ) score was calculated using intraclass correlation coefficients ( ICC [ 1,1 ] ) . RESULTS The kappa value for each of the 11 items ranged from.36 to.80 for individual assessors and from.50 to.79 for consensus ratings generated by groups of 2 or 3 raters . The ICC for the total score was.56 ( 95 % confidence interval=.47-.65 ) for ratings by individuals , and the ICC for consensus ratings was.68 ( 95 % confidence interval=.57-.76 ) . DISCUSSION AND CONCLUSION The reliability of ratings of PEDro scale items varied from " fair " to " substantial , " and the reliability of the total PEDro score was " fair " to " good . Arm cranking is a useful alternative exercise modality for improving walking performance in patients with intermittent claudication ; however , the mechanisms of such an improvement are poorly understood . The main aim of the present study was to investigate the effects of arm-crank exercise training on lower-limb O2 delivery in patients with intermittent claudication . A total of 57 patients with intermittent claudication ( age , 70+/-8 years ; mean+/-S.D. ) were r and omized to an arm-crank exercise group or a non-exercise control group . The exercise group trained twice weekly for 12 weeks . At baseline and 12 weeks , patients completed incremental tests to maximum exercise tolerance on both an arm-crank ergometer and a treadmill .  Respiratory variables were measured breath-by-breath to determine peak VO2 ( O2 uptake ) and ventilatory threshold . Near-IR spectroscopy was used in the treadmill test to determine changes in calf muscle StO2 ( tissue O2 saturation ) . Patients also completed a square-wave treadmill-walking protocol to determine VO2 kinetics . A total of 51 patients completed the study . In the exercise group , higher maximum walking distances ( from 496+/-250 to 661+/-324 m ) and peak VO2 values ( from 17.2+/-2.7 to 18.2+/-3.4 ml.kg-1 of body mass.min-1 ) were recorded in the incremental treadmill test ( P<0.05 ) . After training , there was also an increase in time to minimum StO2 ( from 268+/-305 s to 410+/-366 s ) , a speeding of VO2 kinetics ( from 44.7+/-10.4 to 41.3+/-14.4 s ) and an increase in submaximal StO2 during treadmill walking ( P<0.05 ) . There were no significant changes in the control group . The results suggest that the improvement in walking performance after arm-crank exercise training in patients with intermittent claudication is attributable , at least in part , to improved lower-limb O2 delivery OBJECTIVES Near-infrared spectroscopy provides a noninvasive method of measuring tissue oxygen saturation and has been used to monitor extremity compartment syndrome . Tissue O(2 ) saturation ( StO(2 ) ) is potentially useful in assessing patients with peripheral arterial disease ( PAD ) . The purpose s of this feasibility study are to ( 1 ) explore the diagnostic sensitivity of StO(2 ) in subjects with PAD and symptoms of intermittent claudication ( IC ) compared with normal subjects , and ( 2 ) correlate the change in StO(2 ) during and after exercise with the ankle brachial index ( ABI ) in patients with IC . Material and methods Forty-nine subjects , 35 normal and 14 PAD , from two centers were evaluated in a prospect i ve cross-sectional analysis comparing StO(2 ) by using the InSpectra tissue spectrometer and ABI at rest ( baseline ) and after treadmill exercise . Measurements were obtained at baseline and peak exercise ( normal subjects ) and at baseline , initial claudication distance ( ICD ) and absolute claudication distance ( ACD ) in PAD subjects . Endpoint values were the mean of 15 data points . Times to 50 % of StO(2 ) recovery to baseline ( T(50 ) ) and complete recovery to bas 
    Output:
    
agent
After a long-term resistance training , healthy older adults showed enhanced muscle oxygen extraction capacity , regulation of vessels and vascular endothelium function ; endurance training is reported to improve microvascular blood flow and matching of oxygen delivery to oxygen utilization , muscle oxidative capacity and muscle saturation , and walking sessions results in better muscle oxygen availability and muscle oxygen extraction capacity in older adults with peripheral arterial disease .
This review supports the fact that depending on the clinical status of the participants and the modality , exercise training improves different aspects of the muscle oxygenation in older adults
***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: In older humans , infusions of endothelial agonists suggest endothelial dysfunction , due in part to less nitric oxide (NO)- and prostagl and in (PG)-mediated vasodilatation , and a shift toward PG-mediated vasoconstriction . Ageing can also be associated with lower exercise blood flow ( exercise hyperaemia ) , but the vascular mechanisms mediating this remain unknown . Notably , in young adults , inhibition of NO and PGs during exercise decreases exercise hyperaemia by approximately 20 and approximately 12 % , respectively . We tested our first hypothesis that in older humans inhibition of NO would decrease hyperaemia , but that inhibition of PGs would increase hyperaemia by blocking vasoconstrictor PGs . Fifteen older subjects ( 65 + /- 3 years ) performed dynamic forearm exercise for 20 min ( 20 contractions min(-1 ) ) . Forearm blood flow ( FBF ) was measured beat-to-beat with Doppler ultrasound , while saline or drugs were infused sequentially via brachial artery catheter in the exercising forearm . After achieving steady-state exercise , L-NAME ( 25 mg ) was infused over 5 min to inhibit NO synthase . After a further 2 min of exercise ( saline ) , ketorolac ( 6 mg ) was infused over 5 min to inhibit PGs , followed by a further 3 min of exercise with saline . Drug order was reversed in seven subjects . L-NAME reduced steady-state exercise hyperaemia by 12 + /- 3 % in older subjects ( P<0.01 ) , whereas ketorolac had no net effect on blood flow ( 3 + /- 6 % , P>0.4 ) . The effects of l-NAME and ketorolac were independent of drug order . By comparing these results with our previous results in young adults , we tested our second hypothesis that in older humans inhibition of NO or PGs would have less impact on exercise hyperaemia due to less vasodilatation from these signals . Our results suggest that , compared with young adults , in older humans the relative contribution of NO to exercise hyperaemia is reduced approximately 45 % ( 22 + /- 4 versus 12 + /- 3 % ) , but the role of PG in mediating vasodilatation is lost in ageing human skeletal muscle . Lower exercise hyperaemia in older humans may be mediated in part by less NO- and PG-mediated vasodilatation during exercise The objectives of this study were to examine the effects of opioid administration on the acute cardiorespiratory and muscle oxygenation responses during a repetitive lifting and lowering test ( RLL ) to voluntary fatigue in participants with chronic low back pain ( LBP ) . Written informed consent was obtained from 27 LBP participants ( mean age 50.9 ± 16.4 years ) who completed one testing session during which they were administered a saline placebo and opioid ( 1 μg/kg of fentanyl intravenously ) in r and om order . The participants performed the RLL at a rate that they felt that they could sustain for an 8-h working day . Acute opioid administration increased the total lifting time and total work done during RLL by 35 and 48 % , respectively ( p < 0.05 ) . However , the increased work capacity was accompanied by a significant ( p < 0.05 ) increase in oxygen cost of 22 % per unit amount of work done and significant ( p < 0.05 ) increases in heart rate ( 7 % ) and ventilation rate ( 10 % ) . Near infrared spectroscopic analysis of erector spinae oxygenation and blood volume responses during RLL indicated no significant ( p > 0.05 ) differences between the opioid and placebo phases . These findings suggest that the increased energy cost of lifting as a result of opioid administration was due to enhanced central oxygen transport and not peripheral muscle oxygen extraction BACKGROUND Aging is associated with increased cardiovascular risk and endothelial dysfunction . Since exercise can improve endothelium-dependent vasodilation , in the present study we tested whether long-term physical activity could prevent aging-related endothelial dysfunction . METHODS AND RESULTS In 12 young and elderly ( age 26.9+/-2.3 and 62.9+/-5.8 years , respectively ) healthy sedentary subjects and 11 young and 14 elderly matched athletes ( age 27.5+/-1.9 and 66.4+/-6.1 years , respectively ) , we studied ( with strain-gauge plethysmography ) forearm blood flow modifications induced by intrabrachial acetylcholine ( 0.15 , 0.45 , 1.5 , 4.5 , and 15 microg/100 mL per minute ) , an endothelium-dependent vasodilator , at baseline , during infusion of N(G)-monomethyl-L-arginine ( L-NMMA ) ( 100 microg/100 mL forearm tissue per minute ) , a nitric oxide-synthase inhibitor , vitamin C ( 8 mg/100 mL forearm tissue per minute ) , an antioxidant , and finally under simultaneous infusion of L-NMMA and vitamin C. The response to  sodium nitroprusside ( 1 , 2 , and 4 microg/100 mL forearm tissue per minute ) was also evaluated . In young athletes and sedentary subgroups , vasodilation to acetylcholine was inhibited by L-NMMA and was not changed by vitamin C. In elderly subjects , vasodilation to acetylcholine was blunted as compared with young subjects in both control subjects and athletes , whereas the response to sodium nitroprusside was similar . Moreover , in elderly athletes , vitamin C did not change the vasodilation to acetylcholine . In contrast , in elderly sedentary subjects , the response to acetylcholine was resistant to L-NMMA . In this subgroup , vitamin C increased the vasodilation to acetylcholine and restored the inhibiting effect of L-NMMA . CONCLUSIONS These results suggest that regular physical activity can at least in part prevent the age-induced endothelial dysfunction , probably the restoration of nitric oxide availability consequent to prevention of production of oxidative stress This systematic review examines the effectiveness of current exercise interventions for the management of frailty . Eight electronic data bases were search ed for r and omized controlled trials that identified their participants as “ frail ” either in the title , abstract , and /or text and included exercise as an independent component of the intervention . Three of the 47 included studies utilized a vali date d definition of frailty to categorize participants . Emerging evidence suggests that exercise  has a positive impact on some physical determinants and on all functional ability outcomes reported in this systematic review . Exercise programs that optimize the health of frail older adults seem to be different from those recommended for healthy older adults . There was a paucity of evidence to characterize the most beneficial exercise program for this population . However , multicomponent training interventions , of long duration ( ≥5 months ) , performed three times per week , for 30–45 minutes per session , generally had superior outcomes than other exercise programs . In conclusion , structured exercise training seems to have a positive impact on frail older adults and may be used for the management of frailty This r and omized trial proposed to determine if there were differences in calf muscle StO2 parameters in patients before and after 12 weeks of a traditional walking or walking-with-poles exercise program .  Data were collected on 85 patients who were r and omized to a traditional walking program ( n = 40 ) or walking-with-poles program ( n = 45 ) of exercise training .  Patients walked for 3 times weekly for 12 weeks . Seventy-one patients completed both the baseline and the 12-week follow-up progressive treadmill tests ( n = 36 traditional walking and n = 35 walking-with-poles ) . Using the near-infrared spectroscopy measures , StO2 was measured prior to , during , and after exercise . At baseline , calf muscle oxygenation decreased from 56 ± 17 % prior to the treadmill test to 16 ± 18 % at peak exercise . The time elapsed prior to reaching nadir StO2 values increased more in the traditional walking group when compared to the walking-with-poles group . Likewise , absolute walking time increased more in the traditional walking group than in the walking-with-poles  group . Tissue oxygenation decline during treadmill testing was less for patients assigned to a 12-week traditional walking program when compared to those assigned to a 12-week walking-with-poles program . In conclusion , the 12-week traditional walking program was superior to walking-with-poles in improving tissue deoxygenation in patients with PAD BACKGROUND AND PURPOSE Assessment of the quality of r and omized controlled trials ( RCTs ) is common practice in systematic review s. However , the reliability of data obtained with most quality assessment scales has not been established . This report describes 2 studies design ed to investigate the reliability of data obtained with the Physiotherapy Evidence Data base ( PEDro ) scale developed to rate the quality of RCTs evaluating physical therapist interventions . METHOD In the first study , 11 raters independently rated 25 RCTs r and omly selected from the PEDro data base . In the second study , 2 raters rated 120 RCTs r and omly selected from the PEDro data base , and disagreements were resolved by a third rater ; this generated a set of individual rater and consensus ratings . The process was repeated by independent raters to create a second set of individual and consensus ratings . Reliability of ratings of PEDro scale items was calculated using multirater kappas , and reliability of the total ( summed ) score was calculated using intraclass correlation coefficients ( ICC [ 1,1 ] ) . RESULTS The kappa value for each of the 11 items ranged from.36 to.80 for individual assessors and from.50 to.79 for consensus ratings generated by groups of 2 or 3 raters . The ICC for the total score was.56 ( 95 % confidence interval=.47-.65 ) for ratings by individuals , and the ICC for consensus ratings was.68 ( 95 % confidence interval=.57-.76 ) . DISCUSSION AND CONCLUSION The reliability of ratings of PEDro scale items varied from " fair " to " substantial , " and the reliability of the total PEDro score was " fair " to " good . Arm cranking is a useful alternative exercise modality for improving walking performance in patients with intermittent claudication ; however , the mechanisms of such an improvement are poorly understood . The main aim of the present study was to investigate the effects of arm-crank exercise training on lower-limb O2 delivery in patients with intermittent claudication . A total of 57 patients with intermittent claudication ( age , 70+/-8 years ; mean+/-S.D. ) were r and omized to an arm-crank exercise group or a non-exercise control group . The exercise group trained twice weekly for 12 weeks . At baseline and 12 weeks , patients completed incremental tests to maximum exercise tolerance on both an arm-crank ergometer and a treadmill .  Respiratory variables were measured breath-by-breath to determine peak VO2 ( O2 uptake ) and ventilatory threshold . Near-IR spectroscopy was used in the treadmill test to determine changes in calf muscle StO2 ( tissue O2 saturation ) . Patients also completed a square-wave treadmill-walking protocol to determine VO2 kinetics . A total of 51 patients completed the study . In the exercise group , higher maximum walking distances ( from 496+/-250 to 661+/-324 m ) and peak VO2 values ( from 17.2+/-2.7 to 18.2+/-3.4 ml.kg-1 of body mass.min-1 ) were recorded in the incremental treadmill test ( P<0.05 ) . After training , there was also an increase in time to minimum StO2 ( from 268+/-305 s to 410+/-366 s ) , a speeding of VO2 kinetics ( from 44.7+/-10.4 to 41.3+/-14.4 s ) and an increase in submaximal StO2 during treadmill walking ( P<0.05 ) . There were no significant changes in the control group . The results suggest that the improvement in walking performance after arm-crank exercise training in patients with intermittent claudication is attributable , at least in part , to improved lower-limb O2 delivery OBJECTIVES Near-infrared spectroscopy provides a noninvasive method of measuring tissue oxygen saturation and has been used to monitor extremity compartment syndrome . Tissue O(2 ) saturation ( StO(2 ) ) is potentially useful in assessing patients with peripheral arterial disease ( PAD ) . The purpose s of this feasibility study are to ( 1 ) explore the diagnostic sensitivity of StO(2 ) in subjects with PAD and symptoms of intermittent claudication ( IC ) compared with normal subjects , and ( 2 ) correlate the change in StO(2 ) during and after exercise with the ankle brachial index ( ABI ) in patients with IC . Material and methods Forty-nine subjects , 35 normal and 14 PAD , from two centers were evaluated in a prospect i ve cross-sectional analysis comparing StO(2 ) by using the InSpectra tissue spectrometer and ABI at rest ( baseline ) and after treadmill exercise . Measurements were obtained at baseline and peak exercise ( normal subjects ) and at baseline , initial claudication distance ( ICD ) and absolute claudication distance ( ACD ) in PAD subjects . Endpoint values were the mean of 15 data points . Times to 50 % of StO(2 ) recovery to baseline ( T(50 ) ) and complete recovery to bas 
    Output:
    