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AB Purpose: Previous work identified an asymmetry in tissue desaturation changes in the left and right quadriceps muscles during on-ice skating at maximal speed in males. The effect of changing race distance on the magnitude of desaturation or leg asymmetry is unknown. Methods: Six elite male skaters (age = 23 +/- 1.8 yr, height = 1.8 +/- 0.1 m, mass = 80.1 +/- 5.7 kg, midthigh skinfold thickness = 7 +/- 2 mm) and four elite female skaters (age = 21 +/- 4 yr, height = 1.6 +/- 0.1 m, mass = 65.2 +/- 4.3 kg, midthigh skinfold thickness = 10 +/- 1 mm) were studied. Subjects completed time trials over three race distances. Blood lactate concentration and O2 uptake measurements were combined with near-infrared spectroscopy measures of muscle oxygenation (TSI) and blood volume (tHb) in the right and left vastus lateralis. Results: Neither race distance nor gender had a significant effect on the magnitude of maximal muscle desaturation ([DELTA]TSImax). Pattern of local changes in tHb during individual laps was dependent upon subtle differences in skating technique used for the different race distances. Linear regression analysis revealed asymmetry between the right and left leg desaturation in males during the final stages of each race distance, but not in females. At all race distances, local muscle desaturation reached maximal values much more quickly than global V[spacing dot above]O2peak. Conclusion: The use of wearable near-infrared spectroscopy devices enabled measurement of muscle oxygenation during competitive race simulation, thus providing unique insight into the effects of velocity and technique changes on local muscle oxygenation. This may have implications for training and race pacing in speed skating

Portable near-infrared spectroscopy (NIRS) has been shown to be a useful and reliable tool for monitoring muscle oxygenation and blood volume changes during dynamic exercise in elite athletes. The wearable nature of such technology permits the measurement of specific muscles/muscle groups during realistic sport-specific exercise tasks in an outdoor environment. The aim of this case study was to observe the effect on arm and leg muscle oxygenation of roller skiing over a typical outdoor racing course. Such information is required by coaches in order to ascertain whether an athlete is using the correct technique at different stages of the course. Two wearable NIRS devices (PortaMon, Artinis Medical Systems) were used to compare muscle tissue oxygen saturation (TSI%) and total haemoglobin (tHb) changes in the quadriceps muscle group (vastus lateralis) and a muscle of the upper arm (triceps) during roller skiing. During the flat section, quadriceps ΔTSI remained steady in both subjects, whereas triceps ΔTSI showed a reduction (-10 %). During the steep uphill section of the course, arm and leg TSI decreased equally in one subject (ΔTSI = -10 %), whereas there was a difference between the two muscle groups in the other subject (ΔTSIquadriceps = -2 %; ΔTSItriceps = -7 %). A difference was also seen between subjects during the downhill section of the course. This study presents the first example of the use of portable NIRS to assess oxygenation and blood volume changes in multiple muscle groups during roller skiing in a realistic, outdoor setting.

Portable near-infrared spectroscopy (NIRS) devices were originally developed for use in exercise and sports science by Britton Chance in the 1990s (the RunMan and microRunman series). However, only recently with the development of more robust, and wireless systems, has the routine use in elite sport become possible. As with the medical use of NIRS, finding applications of the technology that are relevant to practitioners is the key issue. One option is to use NIRS to track exercise training-induced adaptations in muscle. Portable NIRS devices enable monitoring during the normal 'field' routine uses to assess fitness, such as repeat sprint shuttle tests. Knowledge about the acute physiological responses to these specific tests has practical applications within team sport training prescription, where development of both central and peripheral determinants of high-intensity intermittent exercise needs to be considered. The purpose of this study was to observe NIRS-detected parameters during a repeat sprint test. We used the PortaMon, a two wavelength spatially resolved NIR spectrometer manufactured by Artinis Inc., to assess NIR changes in the gastrocnemius muscle of both the left and right leg during high-intensity running. Six university standard rugby players were assessed (age 20 ± 1.5 years; height 183 ± 1.0 cm; weight 89.4 ± 5.8 kg; body fat 12.2 ± 3.0 %); the subjects completed nine repeated shuttle runs, which incorporated forward, backward and change of direction movements. Individual sprint time, total time to complete test, blood lactate response (BL), heart rate values (HR) and haemoglobin variables (ΔHHb, ΔtHb, ΔHbO2 and ΔTSI%) were measured. Total time to complete the test was 260 ± 20 s, final blood lactate was 14.3 ± 2.8 mM, and maximal HR 182 ± 5 bpm. NIRS variables displayed no differences between right and left legs. During the test, the group-averaged data showed a clear decrease in HbO2 (max. decrease 11.41 ± 4.95 μM), increase in HHb (max. increase 17.65 ± 4.48 μM) and drop in %TSI (max. drop - 24.44 ± 4.63 %). tHb was largely unchanged. However, large interindividual differences were seen for all the NIRS parameters. In conclusion, this observational study suggests that a portable NIRS device is both robust and sensitive enough to detect haemoglobin changes during a high-intensity repeated shuttle run test. It therefore has the possibility to be used to assess exercise training-induced adaptations following a specific training protocol. However, it is at present unclear, given the individual variability, whether NIRS can be used to assess individual performance. We recommend that future studies report individual as well as group data.

Portable near-infrared spectroscopy (NIRS) has been shown to be a useful and reliable tool for monitoring muscle oxygenation and blood volume changes during dynamic exercise in elite athletes. The wearable nature of such technology permits the measurement of specific muscles/muscle groups during realistic sport-specific exercise tasks in an outdoor environment. The aim of this case study was to observe the effect on arm and leg muscle oxygenation of roller skiing over a typical outdoor racing course. Such information is required by coaches in order to ascertain whether an athlete is using the correct technique at different stages of the course. Two wearable NIRS devices (PortaMon, Artinis Medical Systems) were used to compare muscle tissue oxygen saturation (TSI%) and total haemoglobin (tHb) changes in the quadriceps muscle group (vastus lateralis) and a muscle of the upper arm (triceps) during roller skiing. During the flat section, quadriceps ΔTSI remained steady in both subjects, whereas triceps ΔTSI showed a reduction (−10 %). During the steep uphill section of the course, arm and leg TSI decreased equally in one subject (ΔTSI = −10 %), whereas there was a difference between the two muscle groups in the other subject (ΔTSIquadriceps = −2 %; ΔTSItriceps = −7 %). A difference was also seen between subjects during the downhill section of the course. This study presents the first example of the use of portable NIRS to assess oxygenation and blood volume changes in multiple muscle groups during roller skiing in a realistic, outdoor setting.

PURPOSE: It has been suggested that, because of the low sitting position in short-track speed skating, muscle blood flow is restricted, leading to decreases in tissue oxygenation. Therefore, wearable wireless-enabled near-infrared spectroscopy (NIRS) technology was used to monitor changes in quadriceps muscle blood volume and oxygenation during a 500-m race simulation in short-track speed skaters. METHODS: Six elite skaters, all of Olympic standard (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm), were studied. Subjects completed a 500-m race simulation time trial (TT). Whole-body oxygen consumption was simultaneously measured with muscle oxygenation in right and left vastus lateralis as measured by NIRS. RESULTS: Mean time for race completion was 44.8 ± 0.4 s. VO 2 peaked 20 s into the race. In contrast, muscle tissue oxygen saturation (TSI%) decreased and plateaued after 8 s. Linear regression analysis showed that right leg TSI% remained constant throughout the rest of the TT (slope value = 0.01), whereas left leg TSI% increased steadily (slope value = 0.16), leading to a significant asymmetry (P < 0.05) in the final lap. Total muscle blood volume decreased equally in both legs at the start of the simulation. However, during subsequent laps, there was a strong asymmetry during cornering; when skaters traveled solely on the right leg, there was a decrease in its muscle blood volume, whereas an increase was seen in the left leg. CONCLUSIONS: NIRS was shown to be a viable tool for wireless monitoring of muscle oxygenation. The asymmetry in muscle desaturation observed on the two legs in short-track speed skating has implications for training and performance. © 2012 by the American College of Sports Medicine.