Muscle Oxygenation Rather Than VO2max as a Strong Predictor of Performance in Sprint Canoe-Kayak

Characterization of muscle oxygenation response in well-trained handcyclists

PURPOSE

 Peripheral responses might be important in handcycling, given the involvement of small muscles compared to other exercise modalities. Therefore, the goal of this study was to compare changes in muscle oxygen saturation (∆SmO2) and deoxyhemoglobin level (∆[HHb]) between different efforts and muscles.

METHODS

 Handcyclists participated in a Wingate, a maximal incremental test and a 20-min time-trial (TT). Oxygen uptake (VO2) as well as ∆SmO2, ∆[HHb], deoxygenation and reoxygenation rates in the triceps brachii (TB), biceps brachii (BB), anterior deltoid (AD) and extensor carpi radialis brevis (ER) were measured.

RESULTS

 ER ∆[HHb]max was 37% greater in the incremental test than in the Wingate (ES = 0.392, P = 0.031). TT mean power (W/kg) was associated with BB ∆SmO2min measured in the incremental test (r = -0.998 [-1.190, -0.806], P = 0.002) and in the Wingate (r = -0.994 [-1.327, -0.661], P = 0.006). MAP (W/kg) was associated with Wingate BB ∆SmO2min (r = -0.983 [-0.999, -0.839], P = 0.003), and Wingate peak (r = 0.649 [0.379, 0.895], P = 0.008) and mean power (W/kg) (r = 0.925 [0.752, 0.972], P = 0.003) was associated with right handgrip force. The strongest physiological predictor for TT performance was BB ∆SmO2min in the incremental test (P = 0.002, r2 = 0.993, SEE 0.016 W/kg), Wingate BB ∆SmO2min for MAP (P = 0.003, r2 = 0.956, SEE 0.058 W/kg) and right handgrip force for Wingate peak power (P = 0.005, r2 = 0.856, SEE 0.551 W/kg).

CONCLUSION

 Peripheral aerobic responses (muscle oxygenation) were predictive of handcycling performance.

Muscle Oximetry in Sports Science: An Updated Systematic Review

BACKGROUND

In the last 5 years since our last systematic review, a significant number of articles have been published on the technical aspects of muscle near-infrared spectroscopy (NIRS), the interpretation of the signals and the benefits of using the NIRS technique to measure the physiological status of muscles and to determine the workload of working muscles.

OBJECTIVES

Considering the consistent number of studies on the application of muscle oximetry in sports science published over the last 5 years, the objectives of this updated systematic review were to highlight the applications of muscle oximetry in the assessment of skeletal muscle oxidative performance in sports activities and to emphasize how this technology has been applied to exercise and training over the last 5 years. In addition, some recent instrumental developments will be briefly summarized.

METHODS

Preferred Reporting Items for Systematic Reviews guidelines were followed in a systematic fashion to search, appraise and synthesize existing literature on this topic. Electronic databases such as Scopus, MEDLINE/PubMed and SPORTDiscus were searched from March 2017 up to March 2023. Potential inclusions were screened against eligibility criteria relating to recreationally trained to elite athletes, with or without training programmes, who must have assessed physiological variables monitored by commercial oximeters or NIRS instrumentation.

RESULTS

Of the identified records, 191 studies regrouping 3435 participants, met the eligibility criteria. This systematic review highlighted a number of key findings in 37 domains of sport activities. Overall, NIRS information can be used as a meaningful marker of skeletal muscle oxidative capacity and can become one of the primary monitoring tools in practice in conjunction with, or in comparison with, heart rate or mechanical power indices in diverse exercise contexts and across different types of training and interventions.

CONCLUSIONS

Although the feasibility and success of the use of muscle oximetry in sports science is well documented, there is still a need for further instrumental development to overcome current instrumental limitations. Longitudinal studies are urgently needed to strengthen the benefits of using muscle oximetry in sports science.

Use of NIRS to explore skeletal muscle oxygenation during different training sessions in professional boxing

PURPOSE

The physiological examination of boxing has been limited to systemic response in amateur athletes. The demands of professional boxing have been overlooked, despite the different competition format. We sought to determine the physiological demands placed on skeletal muscle in professional boxing.

METHODS

Ten male professional boxers (age 26 ± 5 years, height 177 ± 4 cm, weight 71 ± 6 kg) were recruited for this observational study. On different days, the athletes completed 6 × 3 min rounds of pad, bag or spar-based training with 1 min recovery between each round. Prior to each session, participants put on a heart rate monitor and near-infrared spectroscopy attached to the belly of the rectus femoris muscle to record heart rate and muscle oxygenation.

RESULTS

There were significantly less punches thrown in sparring compared to other training modalities (p < 0.001). Skeletal muscle oxygenation across training modalities consisted of a delay, fast desaturation and steady state. Across rounds there was a significant increase in time delay for desaturation (p = 0.016), rate of fast desaturation (p < 0.001) and duration of fast desaturation (p = 0.019). There was a significant difference in sparring for the heart rate where skeletal muscle oxygenation changes occurred compared to pads or bag sessions (p < 0.001).

CONCLUSION

The findings highlight differences in the skeletal muscle response to the different training modalities. Practitioners need to be aware of the muscular demands of each session to allow optimal adaptation across a training camp. Training needs to allow the skeletal muscle to achieve a new oxygenation steady state rapidly to promote efficient performance across rounds.

Cranberry supplementation improves physiological markers of performance in trained runners

PURPOSE

Cranberries have the highest polyphenol and antioxidant capacity among fruits and vegetables and may protect against exercise-induced free radical production, consequently improving performance. This study aimed to investigate the effect of polyphenol-rich cranberry extract (CE) on time-trial performance and lactate response following exercise.

METHODS

A total of 14 trained runners were tested at i) baseline, ii) 2 h following an acute CE dose (0.7 g/kg of body mass), and iii) 4 weeks after daily supplement consumption (0.3 g/kg of body mass). At each time point, runners performed a 1500-m race followed by a 400-m race where the live vastus lateralis oxygenation changes were determined by near-infrared spectroscopy and blood lactate was measured at rest and 1 and 3 min after each trial. The Shapiro-Wilk test and repeated-measures analysis of variance were used to establish significance (P <0.05).

RESULTS

Cranberry supplementation over 28 d improved aerobic performance during the 1500-m time trial, whereas the acute dose had no effect. More specifically, muscle reoxygenation rates were significantly faster after 28 d compared to baseline (P = 0.04; η² = 0.29), and a trend towards slower deoxygenation rate was observed (P = 0.13; η² = 0.20). Chronic CE consumption also buffered the post-exercise lactate response for the 400-m race (P = 0.01; η² = 0.27), while no effects were seen for the longer race.

CONCLUSION

Our results suggest that cranberry supplementation may have ergogenic effects, as it improves physiological markers of performance during short- and long-distance running.

Blood flow restriction training on physical parameters in elite male canoe athletes

BACKGROUND

To investigate the effect blood flow restriction (BFR) exercises on muscle size, strength and athletic performance in elite canoe athletes aged 18 to 25 years.

METHODS

This was a randomized controlled trial. The participants were divided into 2 groups: the intervention group (INT-gr) (n = 17, age: 18.59 ± 0.71 years) and the control group (CONT-gr) (n = 16, age: 18.81 ± 1.11 years). Anthropometric measurements, muscle size measured by ultrasound (US), strength measurements with an isokinetic dynamometer, and ergometer performance with an indoor ergometer were conducted before and after the exercise program. Knee flexion and extension and leg press one-repetition maximum (1 RM) tests were performed to determine the participants' training program. The INT-gr performed 1 RM 30% resistance training + BFR for 8 weeks, while the CONT-gr performed 1 RM 30% resistance training (RT) without BFR with their routine training program. US was used to measure the cross sectional area (CSA) and thickness of the quadriceps femoris (QF) and Hamstring (H) muscles in the pre-post design, and the isokinetic dynamometer was used to measure the strength of bilateral 60˚/s and 300˚/s peak torque (PT) values of the QF and H. Sports performance was tested on an indoor ergometer at distances of 200, 500, and 1000 m.

RESULTS

The changes in bilateral rectus femoris (RF) CSA and VL thickness measurements in the INT-gr were significant (P < .05). Ergometer performance measurements showed a significant improvement over CONT-gr at all distances (P < .05). In terms of strength scores measured by the isokinetic dynamometer, the right QF and H 300˚/s and the left QF 60˚/s PT values were significantly in favor of INT-gr.

CONCLUSION

BFR exercises are effective to increase strength, muscle size, and ergometer performance in elite canoe athletes.

Anaerobic Speed Reserve and Performance Relationships Between International and World-Class Short-Track Speed Skating

PURPOSE

Short-track speed skating race distances of 500, 1000, and 1500 m that last ∼40 seconds to ∼2.5 minutes and require a maximal intensity at speeds beyond maximal oxygen uptake (VO2max). Recently, the anaerobic speed reserve (ASR) has been applied by scientists and coaches in middle-distance sports to deepen understanding of 1- to 5-minute event performance where different physiological profiles (speed, hybrid, and endurance) can have success.

METHODS

World-class (women, n = 2; men, n = 3) and international-level (women, n = 4; men, n = 5) short-track speed skaters completed maximal aerobic speed and maximal skating speed tests. ASR characteristics were compared between profiles and associated with on-ice performance.

RESULTS

World-class athletes raced at a lower %ASR in the 1000- (3.1%; large; almost certainly) and 1500-m (1.8%; large; possibly) events than international athletes. Men's and women's speed profiles operated at a higher %ASR in the 500-m than hybrid and endurance profiles, whereas in the 1500-m, endurance profiles worked at a substantially lower %ASR than hybrid and speed profiles. Women's 500-m performance is very largely associated with maximal skating speed, while women's maximal aerobic speed appears to be a key determining factor in the 1000- and 1500-m performance.

CONCLUSION

World-class short-track speed skaters can be developed in speed, hybrid, and endurance profiles but achieve their performance differently by leveraging their strongest characteristics. These results show nuanced differences between men's and women's 500-, 1000- and 1500-m event performance across ASR profile that unlock new insights for individualizing athlete performance in these disciplines.

Comparative analysis of cardiorespiratory fitness, bio-motor abilities, and body composition indicators among sprint kayakers of different age groups and expertise levels

This study compared cardiorespiratory fitness, bio-motor abilities, and body composition indexes of sprint kayakers categorized into three different age groups and two expertise levels of international- and club-level athletes. Seventy-three male juniors (n = 14, age = 16.2 ± 0.8), under 23 [U23 (n = 15, age = 20.2 ± 1.6)], professionals (n = 16, age = 27.1 ± 4.8), club-level (n = 15, age = 26.9 ± 6.6), and international-level (n = 13, age = 27.3 ± 3.2) sprint kayakers were studied. Cardiorespiratory fitness (assessed using incremental exercise test), 500 and 1,000-m paddling performance (assessed using kayak ergometer), upper-body power (assessed using 30 s all-out Wingate test) and strength (assessed through one repetition tests for bench press, cable row, and prone bench pull exercises), as well as body composition indexes (measured using dual-energy X-ray absorptiometry) were evaluated on four occasions separated by 48 h recovery. U23 and, especially, professionals indicated significantly (p < 0.05) greater outcomes for the majority of the cardiorespiratory fitness parameters [maximal oxygen uptake (VO2max), velocity corresponding to VO2max, Oxygen pulse, maximal ventilation, and second ventilatory threshold] and 500 and 1,000-m performance. U23 and professional sprint kayakers significantly (p < 0.05) differed in the first ventilatory threshold and 500, and 1,000-m performance but not in VO2max or the second ventilatory threshold. Professionals also showed a lower fat mass, higher muscle mass, and higher strength (bench press, prone bench pull, and seated cable row) and power than U23 and junior kayakers. Strength and power indicators had significantly greater values in U23 athletes compared to juniors. International-level athletes also showed superior VO2max, velocity corresponding to VO2max, middle (500-m), and long-distance (1,000-m) time trial performance, strength and power, lower fat, and higher muscle mass than club-level sprint kayakers. Cardiorespiratory fitness (particularly ventilatory threshold), body composition, and muscle strength/power are the best differentiating factors for sprint kayakers of different ages and expertise levels. These findings could aid coaches in prescribing training programs focusing on improving determining factors in paddling performance, as well as in predicting performance and identifying talent.

Effects of a paddling-based high-intensity interval training prescribed using anaerobic speed reserve on sprint kayak performance

The aim of this study was to investigate physiological and performance adaptations to high-intensity interval training (HIIT) prescribed as a proportion of anaerobic speed reserve (ASR) compared to HIIT prescribed using maximal aerobic speed (MAS). Twenty-four highly trained sprint kayak athletes were randomly allocated to one of three 4-weak conditions (N = 8) (ASR-HIIT) two sets of 6 × 60 s intervals at ∆%20ASR (MAS-HIIT) six 2 min paddling intervals at 100% maximal aerobic speed (MAS); or controls (CON) who performed six sessions/week of 1-h traditional endurance paddling at 70%-80% maximum HR. A graded exercise test was performed on a kayak ergometer to determine peak oxygen uptake (V̇O_2peak), MAS, V̇O₂/HR, and ventilatory threshold. Also, participants completed four consecutive upper-body wingate tests to asses peak and average power output. Significant increases in V̇O_2peak (ASR-HIIT = 6.9%, MAS-HIIT = 4.8%), MAS (ASR-HIIT = 7.2%, MAS-HIIT = 4.8%), ASR (ASR-HIIT = -25.1%, MAS-HIIT = -15.9%), upper-body Wingate peak power output and average power output (p < 0.05 for both HIIT groups) were seen compared with pre-training. Also, ASR-HIIT resulted in a significant decrease in 500-m - 1.9 % , and 1,000 - m   - 1.5 % paddling time. Lower coefficient of variation values were observed for the percent changes of the aforementioned factors in response to ASR-HIIT compared to MAS-HIIT. Overall, a short period of ASR-HIIT improves 500-m and 1,000-m paddling performances in highly trained sprint kayak athletes. Importantly, inter-subject variability (CV) of physiological adaptations to ASR-HIIT was lower than MAS-HIIT. Individualized prescription of HIIT using ASR ensures similar physiological demands across individuals and potentially facilitates similar degrees of physiological adaptation.

All about oxygen: using near-infrared spectroscopy to understand bioenergetics

The interchange among the energy-providing phosphagen, glycolytic, and aerobic systems during exercise is often poorly understood by beginning students in exercise physiology. Exercise is oftentimes thought of as being aerobic or anaerobic, with the body progressing sequentially from one system to the next, although the energy systems work synergistically to produce energy from the onset of exercise, and all ultimately use oxygen. Traditional methods of teaching these concepts using only indirect calorimetry and a metabolic cart can be misleading. Relatively inexpensive noninvasive monitors of muscle oxygenation levels ([Formula: see text]) provide a useful tool to help students better understand the contribution and timing of these three systems of ATP generation and convey the concept that ultimately all energy production in the human body is oxygen dependent. In this laboratory, students use near-infrared spectroscopy (NIRS) to visualize oxygen utilization by skeletal muscle during exercise by devising three exercise unique protocols, with each designed to stress a different energy system. Students then perform their protocols while using NIRS to measure and analyze [Formula: see text]. Students generate graphs with collected data, allowing them to visualize and appreciate oxygen consumption during all three protocols as well as elevated oxygen consumption after exercise. The students learn that any exercise is really all about oxygen.NEW & NOTEWORTHY Traditional methods of teaching bioenergetics using indirect calorimetry and a metabolic cart may be misleading. Recent advances in technology have made near-infrared spectroscopy (NIRS) a relatively inexpensive, noninvasive means of monitoring muscle oxygen levels during exercise. In this laboratory activity, NIRS devices are used for hands-on exploration of the synergistic nature of the energy systems, allowing students to appreciate the synergistic nature of the energy systems and how all exercise is really all about oxygen.

Muscle Oxygenation Measured with Near-Infrared Spectroscopy Following Different Intermittent Training Protocols in a World-Class Kayaker-A Case Study

Training elite kayakers at a distance of 1000 m is associated with aerobic and anaerobic metabolism, while intermittent training, in a variety of forms, is one of the effective ways to improve cardiorespiratory and metabolic function. Thus, this study aimed to investigate muscle oxygenation responses during repetition training (RT), interval training (IT), and sprint interval training (SIT). Near-infrared spectroscopy (NIRS) monitors were placed on the latissimus dorsi (LD), pectoralis major (PM), and vastus lateralis (VL) of a world-class kayaker during their preparatory period. The intensity of work, relief, and recovery intervals were the independent variables that were manipulated using three different training protocols. The inferential analysis between intermittent training protocols showed significant differences for all variables except total the hemoglobin (tHb) index in LD during bout 2 (F = 2.83, p = 0.1, ηp2 = 0.205); bout 3 (F = 2.7, p = 0.125, ηp2 = 0.193); bout 4 (F = 1.8, p = 0.202, ηp2 = 0.141); and bout 6 (F = 1.1, p = 0.327, ηp2 = 0.092). During the rest bouts, all training protocols showed significant differences for all variables except muscle oxygen saturation (SmO₂) in the VL during bout 5 (F = 4.4, p = 0.053, ηp2 = 0.286) and tHb in VL during bout 1 (F = 2.28, p = 0.132, ηp2 = 0.172); bout 2 (F = 0.564, p = 0.561, ηp2 = 0.049); bout 3 (F = 1.752, p = 0.205, ηp2 = 0.137); bout 4 (F = 1.216, p = 0.301, ηp2 = 0.1); and bout 6 (F = 4.146, p = 0.053, ηp2 = 0.274). The comparison between IT protocols RT and SIT presented similar results. All variables presented higher values during SIT, except HR results. Finally, the comparison between IT and SIT showed significant differences in several variables, and a clear trend was identified. The results of this study suggest that the application of different intermittent exercise protocols promotes distinct and significant changes in the peripheral effect of muscle oxygenation in response to training stimuli and may be internal predictors of hemodynamic and metabolic changes.

Usefulness of Portable Device to Establish Differences in Muscle Oxygenation Between the Wingate Test and Graded Exercise Test: Effect of Gender on Anaerobic and Aerobic Capacity in Speed Skaters

The aim of this study was to compare the oxygenation response in the vastus lateralis muscle (SmO₂) in two types of tests: supramaximal and maximal. Furthermore, gender differences in SmO₂ response to test exercise were assessed and the usefulness of muscle oxygenation measurements in the assessment of anaerobic and aerobic capacity was determined. The Wingate test (WAnT) and the graded exercise test (GXT) to exhaustion were performed on a cycle ergometer to examine 13 female and 14 male speed skaters from the junior and U23 national teams. During both tests, SmO₂ of the vastus lateralis muscle was recorded by near-infrared spectroscopy at baseline (at rest or post warm-up), at exercise, and during recovery. The most significant SmO₂ indices (differences between baseline and post-exercise indices and half time for SmO₂ to reach the maximal post-exercise value) were not significantly different between the tests. Gender was also not a differentiating factor in muscle oxygenation regardless of test type. In the GXT test, half time required for SmO₂ to reach the maximal value correlated negatively with VO_2max and test duration, thus confirming the usefulness of SmO₂ measurements in the assessment of the aerobic capacity of speed skaters. In contrast, the WAnT test showed no significant correlations between exercise indices and muscle oxygenation indices. From the standpoint of the assessment of anaerobic capacity, SmO₂ measurements showed little diagnostic value.

Effects of a New Form of Resistance-Type High-Intensity Interval Training on Cardiac Structure, Hemodynamics, and Physiological and Performance Adaptations in Well-Trained Kayak Sprint Athletes

This study examined the effects of a resistance-type high-intensity interval training (RHIIT) matched with the lowest velocity that elicited V.O_2peak (100% vV.O_2peak) in well-trained kayak sprint athletes. Responses in cardiac structure and function, cardiorespiratory fitness, anaerobic power, exercise performance, muscular strength, and hormonal adaptations were examined. Male kayakers (n = 24, age: 27 ± 4 years) were randomly assigned to one of three 8-wk conditions (N = 8): (RHIIT) resistance training using one-armed cable row at 100% vV.O_2peak; paddling-based HIIT (PHIIT) six sets of paddling at 100% vV.O_2peak; or controls (CON) who performed six sessions including 1-h on-water paddling/sessions at 70–80% maximum HR per week. Significant increases (p < 0.05) in V.O_2peak, vV.O_2peak, maximal cardiac output, resting stroke volume, left ventricular end-systolic dimension, 500-m paddling performance were seen pre- to post-training in all groups. Change in V.O_2peak in response to PHIIT was significantly greater (p = 0.03) compared to CON. Also, 500-m paddling performance changes in response to PHIIT and RHIIT were greater (p = 0.02, 0.05, respectively) than that of CON. Compared with pre-training, PHIIT and RHIIT resulted in significant increases in peak and average power output, maximal stroke volume, end-diastolic volume, ejection fraction, total testosterone, testosterone/cortisol ratio, and 1,000-m paddling performance. Also, the change in 1,000-m paddling performance in response to PHIIT was significantly greater (p = 0.02) compared to that of CON. Moreover, maximum strength was significantly enhanced in response to RHIIT pre- to post-training (p < 0.05). Overall, RHIIT and PHIIT similarly improve cardiac structure and hemodynamics, physiological adaptations, and performance of well-trained kayak sprint athletes. Also, RHIIT enhances cardiorespiratory fitness and muscular strength simultaneously.

The use of muscle near-infrared spectroscopy (NIRS) to assess the aerobic training loads of world-class rowers

The objectives of this study were (1) to characterize the changes in oxygenation derived from muscle near-infrared spectroscopy (NIRS) during aerobic constant-load exercise with intensities close to Maximal Lactate Steady-State (MLSS) and (2) to establish reference values in the world-class rowers, for such workload often included in rowing training programs. Eight senior world-class rowers performed an incremental progressive submaximal exercise test and a 30-minute test on a rowing ergometer. The power corresponding to intensive aerobic training (84±1% of the anaerobic threshold) was adopted as an exercise load in the 30-minute test. The NIRS device was fixed on the vastus lateralis muscle which was active during rowing to record muscle O₂ saturation (SmO₂) and total hemoglobin concentration (THb) at rest and during exercise. Statistically significant increments in blood lactate (LA) and heart rate (HR) were observed, with 1.18±0.61 mmol/l and 10±5 beats/min, respectively, in 30th minute compared to 10th minute in 30-minute test. SmO₂ decreased significantly by 2.9±1.4%, whereas THb did not change. The examinations may suggested the low diagnostic value of THb in constant-load exercise. In each subject, SmO₂ was gradually reduced during the intense aerobic exercise. During workload close to MLSS, the SmO₂ of the vastus lateralis ranged from 14.0±3.13 to 11.1±2.81% in 10 and 30 minutes respectively, with a reduction in muscle oxygenation (ΔSmO₂) exceeding 50%. The non-invasive nature of the NIRS measurement and the continuous monitoring of SmO₂ values are useful in the practice of monitoring training in terms of aerobic training loads.

The effect of HIIT vs. SIT on muscle oxygenation in trained sprint kayakers

PURPOSE

To assess the performance change and physiological adaptations following nine sessions of short high-intensity interval training (HIIT) or sprint-interval training (SIT) in sprint kayakers.

METHODS

Twelve trained kayakers performed an incremental test and 3 time trials (200 m, 500 m and 1000 m) on a kayak ergometer. Oxygen consumption (V̇O₂) and muscle oxygenation of the latissimus dorsi, biceps brachii, and vastus lateralis were measured. Athletes were then paired for sex and V̇O₂max and randomized into a HIIT or a SIT training group, and performed nine training sessions before repeating the tests.

RESULTS

Training improved performance in HIIT (200 m: + 3.8 ± 3.1%, p = 0.06; 500 m: + 2.1 ± 4.1%, p = 0.056; 1000 m: + 3.0 ± 4.6%, p = 0.13) but changes in performance remained within the smallest worthwhile change in SIT (200 m: + 0.8 ± 4.1%, p = 0.59; 500 m: + 0.5 ± 4.1%, p = 0.87; 1000 m: + 1.3 ± 4.6%, p = 0.57). In the 1000 m, training led to a greater deoxygenation in the biceps brachii and vastus lateralis in HIIT, and in the latissimus dorsi in SIT. In HIIT, the best predictors of improvements in 1000 m performance were increases in latissimus dorsi and vastus lateralis maximal deoxygenation.

CONCLUSION

In a group of trained sprint kayakers, greater improvements in performance can be obtained with HIIT compared with SIT, for any distance. Training did not change V̇O₂peak, but increased muscle maximal deoxygenation, suggesting both HIIT and SIT elicit peripheral adaptations. Performance improvement in the 1000 m was associated with increased maximal muscle deoxygenation, reinforcing the contribution of peripheral adaptations to performance in sprint kayaking.

Comparison of Physiological Parameters During On-Water and Ergometer Kayaking and Their Relationship to Performance in Sprint Kayak Competitions

PURPOSE

(1) To compare various physiological indicators of performance during a 5 × 1500-m incremental kayak test performed on an ergometer and on-water and (2) to analyze the relationships between these indicators and the actual competition performance of elite sprint kayakers, aiming to provide information to coaches for evaluating and planning training on-water.

METHODS

A total of 14 male and female German elite sprint kayakers performed an incremental test both on an ergometer and on-water. The tissue saturation index of the musculus (m.) biceps brachii, oxygen consumption, ratings of perceived exertion, and levels of blood lactate were measured and compared with actual racing times. In addition, power output was monitored during ergometer testing only.

RESULTS

Oxygen consumption during the fourth (P = .02; d = 0.32) and final (fifth; P < .001; d = 0.32) steps of incremental testing was higher on-water than on the ergometer. The tissue saturation index of the m. biceps brachii was approximately 21% higher at the end of the ergometer test (P = .002; d = 1.14). During the second (P = .01; d = 0.78), third (P = .005; d = 0.93), and fourth stages (P = .005; d = 1.02), the ratings of perceived exertion for ergometer kayaking was higher. During the final step, power output was most closely correlated to 200- (r = .88), 500- (r = .93), and 1000-m (r = .86) racing times (all Ps < .01).

CONCLUSIONS

During high-intensity kayaking on an ergometer or on-water, the oxygen consumption and tissue saturation index of the m. biceps brachii differ. Furthermore, at moderate to submaximal intensities, the ratings of perceived exertion were higher for ergometer than for on-water kayaking. Finally, of all parameters assessed, the power output during ergometer kayaking exhibited the strongest correlation with actual racing performance.

Prediction of VO2max based on a 3-kilometer running test for water sports athletes

BACKGROUND

No studies have reported the 3-kilometer running test (3KRT) intending to predict VO2max for water sports athletes. Therefore, the purpose of this study was to develop a new model to predict the maximal aerobic capacity (VO2max) for water sports athletes based on 3KRT.

METHODS

One hundred and two water sports athletes completed two sessions of experiments consisting of a maximal graded exercise test (GXT) and a 3KRT. Multiple linear regression was applied to predict VO2max value based on the performance and physiological responses of 3KRT, along with participants' anthropometric and demographic variables. The predicted residual error sum of square (PRESS) and error terms (constant error and total error) were calculated to further evaluate the predictive accuracy.

RESULTS

Two significant prediction models based on elapsed exercise time (T3KRT), post-exercise heart rate (PHR3KRT), body mass, and gender were proposed. One model including PHR3KRT was identified (VO2max=120.77-0.028×T3KRT [second]-0.11×PHR3KRT [bpm]-0.334×body mass [kg]+8.70×gender [1: male, 0: female]), with an adjusted R2 of 0.723. Another model excluding PHR3KRT was also identified (VO2max=103.65-0.034×T3KRT [second]-0.317×Body mass [kg] + 7.89×gender [1: male, 0: female]), with an adjusted R2 of 0.713. Both models were further validated by the result of PRESS statistics.

CONCLUSIONS

This endurance 3-kilometer running test accurately predicted VO2max value for water sports athletes (rowers, canoeists, and kayakers), and the model excluding PHR3KRT would be easier to use.

Effect of a 3-Weeks Training Camp on Muscle Oxygenation, V ˙ O2 and Performance in Elite Sprint Kayakers

Purpose: Peripheral adaptations, as assessed via near-infrared spectroscopy (NIRS) derived changes in muscle oxygenation (SmO2), are good predictors of sprint kayak performance. Therefore, the goal of the present study was to assess changes in SmO2 andV ˙ O2 following a training camp in elite sprint kayakers to evaluate if the training prescribed elicits peripheral adaptations, and to assess associations between training-induced changes in physiological responses and performance. Methods: Eight male elite sprint kayakers, members of the Canadian National Team, performed a 200-m and 1,000-m on-water time trial (TT) before and after a 3-weeks winter training camp. Change in performance,V ˙ O2 and SmO2 of the biceps brachii were assessed in relation to training load. Results: Training load and intensity were increased by ~20% over the course of the training camp, which resulted in a 3.7 ± 1.7% (ES 1.2) and 2.8 ± 2.4% (ES 1.3) improvement in 200-m and 1,000-m performance, respectively. Performance improvement in the 200-m was concomitant to a reduced SmO2, an increasedV ˙ O2 peak and an increased reoxygenation rate after the TT. The 1,000-m TT performance improvement was concurrent with a reduced SmO2 in the last half of the TT and an increasedV ˙ O2 in the first minute of the TT. Conclusion: Our results strongly suggest that peripheral skeletal muscle adaptations occurred in these athletes with the proposed training plan. This further attests the benefit of using portable NIRS as a monitoring tool to track training-induced adaptations in muscle oxygen extraction in elite athletes.

Sustained Muscle Deoxygenation vs. Sustained High VO2 During High-Intensity Interval Training in Sprint Canoe-Kayak

Recent data suggests that peripheral adaptations, i.e., the muscle ability to extract and use oxygen, may be a stronger predictor of canoe-kayak sprint performance compared to VO₂max or central adaptations. If maximizing the time near VO₂max during high-intensity interval training (HIIT) sessions is believed to optimize central adaptations, maximizing the time near maximal levels of muscle desaturation could represent a critical stimulus to optimize peripheral adaptations.

Purpose: Therefore, the purpose of this study was to assess the VO₂, muscle oxygenation and cardiac output responses to various HIIT sessions, and to determine which type of HIIT elicits the lowest muscle oxygenation and the longest cumulated time at low muscle O₂ saturation.

Methods: Thirteen well-trained canoe-kayak athletes performed an incremental test to determine VO₂max and peak power output (PPO), and 4 HIIT sessions (HIIT-15: 40x[15 s at 115%PPO, 15 s at 30%PPO]; HIIT-30: 20x[30 s at 115%PPO, 30 s at 30%PPO]; HIIT-60: 6x[1 min at 130%PPO, 3 min rest]; sprint interval training (SIT): 6x[30 s all-out, 3 min 30 rest]) on a canoe or kayak ergometer. Portable near-infrared spectroscopy monitors were placed on the Latissimus dorsi (LD), Biceps brachii (BB), and Vastus lateralis (VL) during every session to assess changes in muscle O₂ saturation (SmO₂, % of physiological range).

Results: HIIT-15 and HIIT-30 elicited a longer time >90%VO₂max (HIIT-15: 8.1 ± 6.2 min, HIIT-30: 6.8 ± 4.6 min), compared to SIT (1.7 ± 1.3 min, p = 0.006 and p = 0.035) but not HIIT-60 (4.1 ± 1.7 min). SIT and HIIT-60 elicited the lowest SmO₂ in the VL (SIT: 0 ± 1%, HIIT-60: 8 ± 9%) compared to HIIT-15 (26 ± 12%, p < 0.001 and p = 0.007) and HIIT-30 (25 ± 12%, p < 0.001 and p = 0.030). SIT produced the longest time at >90% of maximal deoxygenation in all 3 muscles, with effect sizes ranging from small to very large.

Conclusions: Short HIIT performed on a canoe/kayak ergometer elicits the longest time near VO₂max, potentially conducive to VO₂max improvements, but SIT is needed in order to maximize muscle deoxygenation during training, which would potentially conduct to greater peripheral adaptations.