and hemodynamic in sport, health, and clinical settings. 5 – 7 NIRS provides information on the concentrations of oxygenated hemoglobin and myoglobin (O 2 Hb), deoxygenated hemoglobin and myoglobin (HHb), tissue saturation index (TSI), and hemodynamics of total hemoglobin (tHb) on peripheral muscle
Ade B. Pratama and Tossaporn Yimlamai
Philippe Richard and François Billaut
calculated using the tissue saturation index (TSI [%]) as [O 2 HbMb] divided by ([O 2 HbMb] + [HHbMb]) × 100. The [HHbMb] signal was also taken as an indicator of tissue deoxygenation because this variable is less sensitive than [O 2 HbMb] to perfusion variations and abrupt blood volume changes during
Simon Fryer, Craig Paterson, Ian C. Perkins, Chris Gloster, Mark E.T. Willems and Julia A. Potter
, participants remained still with their hand loosely resting on the hold for 3 min. cw-NIRS and ultrasound were used to obtain TTHR of tissue saturation index (TSI) percentage in the FDP and total forearm blood flow (brachial artery). Near Infrared Spectroscopy A Portalite cw-NIRS device (Artinis Medical
Dennis-Peter Born, Christoph Zinner, Britta Herlitz, Katharina Richter, Hans-Christer Holmberg and Billy Sperlich
The current investigation assessed tissue oxygenation and local blood volume in both vastus lateralis muscles during 3000-m race simulations in elite speed skaters on ice and the effects of leg compression on physiological, perceptual, and performance measures.
Ten (6 female) elite ice speed skaters completed 2 on-ice trials with and without leg compression. Tissue oxygenation and local blood volume in both vastus lateralis muscles were assessed with near-infrared spectroscopy. Continuous measures of oxygen uptake, ventilation, heart rate, and velocity were conducted throughout the race simulations, as well as blood lactate concentration and ratings of perceived exertion before and after the trials. In addition, lap times were assessed.
The investigation of tissue oxygenation in both vastus lateralis muscles revealed an asymmetry (P < .00; effect size = 1.81) throughout the 3000-m race simulation. The application of leg compression did not affect oxygenation asymmetry (smallest P = .99; largest effect size = 0.31) or local blood volume (P = .33; 0.95). Lap times (P = .88; 0.43), velocity (P = .24; 0.84), oxygen uptake (P = .79; 0.10), ventilation (P = .11; 0.59), heart rate (P = .21; 0.89), blood lactate concentration (P = .82; 0.59), and ratings of perceived exertion (P = .19; 1.01) were also unaffected by the different types of clothing.
Elite ice speed skaters show an asymmetry in tissue oxygenation of both vastus lateralis muscles during 3000-m events remaining during the long gliding phases along the straight sections of the track. Based on the data, the authors conclude that there are no performance-enhancing benefits from wearing leg compression under a normal racing suit.
Billy Sperlich, Dennis-Peter Born, Christoph Zinner, Anna Hauser and Hans-Christer Holmberg
To evaluate whether upper-body compression affects power output and selected metabolic, cardiorespiratory, hemodynamic, and perceptual responses during three 3-min sessions of double-poling (DP) sprint.
Ten well-trained male athletes (25 ± 4 y, 180 ± 4 cm, 74.6 ± 3.2 kg) performed such sprints on a DP ski ergometer with and without a long-sleeved compression garment.
Mean power output was not affected by such compression (216 ± 25 W in both cases; P = 1.00, effect size [ES] = 0.00), although blood lactate concentration was lowered (P < .05, ES = 0.50–1.02). Blood gases (ES = 0.07–0.50), oxygen uptake (ES = 0.04–0.28), production of carbon dioxide (ES = 0.01–0.46), heart rate (ES = 0.00–0.21), stroke volume (ES = 0.33–0.81), and cardiac output (ES = 0.20–0.91) were also all unaffected by upper-body compression (best P = 1.00). This was also the case for changes in the tissue saturation index (ES = 0.45–1.17) and total blood content of hemoglobin (ES = 0.09–0.85), as well as ratings of perceived exertion (ES = 0.15–0.88; best P = .96).
The authors conclude that the performance of well-trained athletes during 3 × 3-min DP sprints will not be enhanced by upper-body compression.
David Giles, Vanesa España Romero, Inmaculada Garrido, Alejandro de la O Puerta, Keeron Stone and Simon Fryer
To examine differences in oxygenation kinetics in the nondominant and dominant flexor digitorum profundus (FDP) of rock climbers.
Participants were 28 sport climbers with a range of on-site abilities (6a+ to 8a French Sport). Using near-infrared spectroscopy, oxygenation kinetics of the FDP was assessed by calculating the time to half recovery (t 1/2 recovery) of the tissue-saturation index (TSI) after 3–5 min of ischemia.
A 2-way mixed-model ANOVA found a nonsignificant interaction (P = .112) for TSI by sex. However, there was a significant main effect (P = .027) of handedness (dominant vs nondominant FDP). The dominant forearm recovered 13.6% faster (t 1/2 recovery mean difference = 1.12 s, 95% CI 0.13–2.10 s) than the nondominant FDP. This was not affected by 6-mo on-site climbing ability or sex (P = .839, P = .683).
Significant intraindividual differences in oxygenation kinetics of the FDP were found. Improvements in oxygenation kinetics in the FDP are likely due to the abilities of the muscle to deliver, perfuse, and consume oxygen. These enhancements may be due to structural adaptations in the microvasculature, such as an increase in capillary density and enhanced improvement in capillary filtration.
Dennis-Peter Born, Thomas Stöggl, Mikael Swarén and Glenn Björklund
To investigate the cardiorespiratory and metabolic response of trail running and evaluate whether heart rate (HR) adequately reflects the exercise intensity or if the tissue-saturation index (TSI) could provide a more accurate measure during running in hilly terrain.
Seventeen competitive runners (4 women, V̇O2max, 55 ± 6 mL · kg–1 · min–1; 13 men, V̇O2max, 68 ± 6 mL · kg–1 · min–1) performed a time trial on an off-road trail course. The course was made up of 2 laps covering a total distance of 7 km and included 6 steep uphill and downhill sections with an elevation gain of 486 m. All runners were equipped with a portable breath-by-breath gas analyzer, HR belt, global positioning system receiver, and near-infrared spectroscopy (NIRS) device to measure the TSI.
During the trail run, the exercise intensity in the uphill and downhill sections was 94% ± 2% and 91% ± 3% of maximal heart rate, respectively, and 84% ± 8% and 68% ± 7% of V̇O2max, respectively. The oxygen uptake (V̇O2) increased in the uphill sections and decreased in the downhill sections (P < .01). Although HR was unaffected by the altering slope conditions, the TSI was inversely correlated to the changes in V̇O2 (r = –.70, P < .05).
HR was unaffected by the continuously changing exercise intensity; however, TSI reflected the alternations in V̇O2. Recently used exclusively for scientific purposes, this NIRS-based variable may offer a more accurate alternative than HR to monitor running intensity in the future, especially for training and competition in hilly terrain.
Richard Ebreo, Louis Passfield and James Hopker
start of each exercise protocol. An absolute measure of tissue saturation index (TSI%) was also recorded throughout the exercise trial. Skinfold thickness was measured at the site of the NIRS device over the vastus lateralis muscle in the seated position using Harpenden skinfold calipers (British
Sarah J. Willis, Grégoire P. Millet and Fabio Borrani
absolute tissue saturation index (TSI) values as the average of the last 60 seconds of the stage based on spatial resolved spectroscopy. When considering this normalization relative to the submaximal stage, intensities were similar between limbs, with an average of 45% of submaximal workload for legs and
Myriam Paquette, François Bieuzen and François Billaut
upper body musculature. VO 2 max in our study was similar to VO 2 max reported for elite senior kayakers or canoeists elsewere 5 , 6 , 21 , 24 and higher than VO 2 max values reported for elite or subelite junior athletes. 2 , 10 SmO 2 values were also lower than the tissue saturation index reported