Purpose The purpose of the present study was to evaluate the Pearson correlations between hemodynamic parameters obtained with near infrared spectroscopy (NIRS), namely total hemoglobin (tHb) and tissue oxygen index (...Purpose The purpose of the present study was to evaluate the Pearson correlations between hemodynamic parameters obtained with near infrared spectroscopy (NIRS), namely total hemoglobin (tHb) and tissue oxygen index (TOI %), as indica-tors of blood flow and oxygen extraction, and myoelectric parameters obtained with surface multichannel electromyography (sEMG), namely fractal dimension (FD) and conduction velocity (CV) slopes, as descriptors of central and peripheral fatigue, during sustained high level isometric contractions at 60% maximal voluntary contraction (MVC), in elderly subjects. Methods Ten recreationally healthy elderly subjects (age 67.7 ± 4.6 years), 5 males and 5 females, performed one isometric contraction of the elbow flexors at 120° joint angle at 60% of MVC until exhaustion in two subsequent trials 1 week apart, one for the sEMG and the other one for NIRS recordings from the biceps brachii. Results A negative strong Pearson’s correlation between TOI % slope in the functional hyperemic phase (HP) of contrac-tion and a positive correlation between the slope of TOI % recorded during the ischemic phase (IP) and the CV slope were found (r = − 0.76, P < 0.05;r = 0.91, P < 0.01, respectively). A negative strong correlation between tHb IP slope and tHb HP slope and TOI % IP slope and TOI % HP slope (r = − 0.78, P < 0.01;r = − 0.78, P < 0.01, respectively) were also found. No correlation was found between FD slope and hemodynamic parameters (FD slope vs. HP tHb slope, r = − 0.19;FD slope vs. IP tHb slope, r = 0.16;FD slope vs. HP TOI % slope, r = 0.19;FD slope vs. IP TOI % slope, r = 0.27). Conclusion In aged individuals, CV slope correlated with muscle O2 desaturation (TOI %) rather than reduced muscle blood flow (tHb) in the ischemic phase of isometric contraction to exhaustion. No correlations were found between myoelectric manifestations of central fatigue (FD slope) and data obtained by NIRS.展开更多
Purposes In kettlebell sport(KS)half marathon,the lift of the kettlebell is required for the highest number of repetitions in 30 min.No data are available on cardiorespiratory and metabolic responses during this exerc...Purposes In kettlebell sport(KS)half marathon,the lift of the kettlebell is required for the highest number of repetitions in 30 min.No data are available on cardiorespiratory and metabolic responses during this exercise routine.The aim of the study was to evaluate cardiopulmonary and metabolic responses to KS half marathon compared to 30 min treadmill running,chosen as a reference paradigm of aerobic exercise,at the same average oxygen consumption(VO_(2)).Methods A male elite KS athlete was enrolled in two trials separated by 7 days of rest.In the first trial,one-hand long-cycle KS exercise with a 1/3 body weight kettlebell was performed for 30 min(kettlebell half marathon,KT);in the second trial,30 min treadmill running(TR)was performed at the same average VO2 measured in the first trial(speed 9-10 km/h at 1°uphill inclination).Metabolic and cardiopulmonary assessments[respiratory exchange ratio(RER),tidal volume(TV),breathing frequency(f),minute ventilation(VE)],blood lactate(BL)kinetics,heart rate(HR),and blood pressure(BP)were measured in both experimental sessions.Results The average VO_(2) was 33.3 mL/min/kg in KT and 30.6 mL/min/kg in TR.The subject achieved RER_(peak) 1.17,RER_(mean) 0.98,HR_(peak) 172 bpm(94% HR_(max)),HR_(mean) 86% of HR_(max),BP_(peak) 220/100 mmHg in KT,BL_(peak) 7.2 mmol/L(during trial)in KT and RER_(peak) 1.13,RER_(mean) 0.89,HR_(peak) 142 bpm(78%HR_(max)),HR_(mean) 70% of HR_(max),BP_(peak) 160/80 mmHg,BL_(peak) 3.5 mmol/L(4 min after trial)mmol/L in TR.Conclusion Data indicate that a KS half marathon determines much higher cardiopulmonary and metabolic responses to treadmill running performed at similar VO_(2).展开更多
文摘Purpose The purpose of the present study was to evaluate the Pearson correlations between hemodynamic parameters obtained with near infrared spectroscopy (NIRS), namely total hemoglobin (tHb) and tissue oxygen index (TOI %), as indica-tors of blood flow and oxygen extraction, and myoelectric parameters obtained with surface multichannel electromyography (sEMG), namely fractal dimension (FD) and conduction velocity (CV) slopes, as descriptors of central and peripheral fatigue, during sustained high level isometric contractions at 60% maximal voluntary contraction (MVC), in elderly subjects. Methods Ten recreationally healthy elderly subjects (age 67.7 ± 4.6 years), 5 males and 5 females, performed one isometric contraction of the elbow flexors at 120° joint angle at 60% of MVC until exhaustion in two subsequent trials 1 week apart, one for the sEMG and the other one for NIRS recordings from the biceps brachii. Results A negative strong Pearson’s correlation between TOI % slope in the functional hyperemic phase (HP) of contrac-tion and a positive correlation between the slope of TOI % recorded during the ischemic phase (IP) and the CV slope were found (r = − 0.76, P < 0.05;r = 0.91, P < 0.01, respectively). A negative strong correlation between tHb IP slope and tHb HP slope and TOI % IP slope and TOI % HP slope (r = − 0.78, P < 0.01;r = − 0.78, P < 0.01, respectively) were also found. No correlation was found between FD slope and hemodynamic parameters (FD slope vs. HP tHb slope, r = − 0.19;FD slope vs. IP tHb slope, r = 0.16;FD slope vs. HP TOI % slope, r = 0.19;FD slope vs. IP TOI % slope, r = 0.27). Conclusion In aged individuals, CV slope correlated with muscle O2 desaturation (TOI %) rather than reduced muscle blood flow (tHb) in the ischemic phase of isometric contraction to exhaustion. No correlations were found between myoelectric manifestations of central fatigue (FD slope) and data obtained by NIRS.
文摘Purposes In kettlebell sport(KS)half marathon,the lift of the kettlebell is required for the highest number of repetitions in 30 min.No data are available on cardiorespiratory and metabolic responses during this exercise routine.The aim of the study was to evaluate cardiopulmonary and metabolic responses to KS half marathon compared to 30 min treadmill running,chosen as a reference paradigm of aerobic exercise,at the same average oxygen consumption(VO_(2)).Methods A male elite KS athlete was enrolled in two trials separated by 7 days of rest.In the first trial,one-hand long-cycle KS exercise with a 1/3 body weight kettlebell was performed for 30 min(kettlebell half marathon,KT);in the second trial,30 min treadmill running(TR)was performed at the same average VO2 measured in the first trial(speed 9-10 km/h at 1°uphill inclination).Metabolic and cardiopulmonary assessments[respiratory exchange ratio(RER),tidal volume(TV),breathing frequency(f),minute ventilation(VE)],blood lactate(BL)kinetics,heart rate(HR),and blood pressure(BP)were measured in both experimental sessions.Results The average VO_(2) was 33.3 mL/min/kg in KT and 30.6 mL/min/kg in TR.The subject achieved RER_(peak) 1.17,RER_(mean) 0.98,HR_(peak) 172 bpm(94% HR_(max)),HR_(mean) 86% of HR_(max),BP_(peak) 220/100 mmHg in KT,BL_(peak) 7.2 mmol/L(during trial)in KT and RER_(peak) 1.13,RER_(mean) 0.89,HR_(peak) 142 bpm(78%HR_(max)),HR_(mean) 70% of HR_(max),BP_(peak) 160/80 mmHg,BL_(peak) 3.5 mmol/L(4 min after trial)mmol/L in TR.Conclusion Data indicate that a KS half marathon determines much higher cardiopulmonary and metabolic responses to treadmill running performed at similar VO_(2).
