Optimizing physical performance is a major goal in current physiology. However, basic understanding of combining high sprint and endurance performance is currently lacking. This study identifies critical determinants of combined sprint and endurance performance using multiple regression analyses of physiologic determinants at different biologic levels. Cyclists, including 6 international sprint, 8 team pursuit, and 14 road cyclists, completed a Wingate test and 15-km time trial to obtain sprint and endurance performance results, respectively. Performance was normalized to lean body mass 2/3 to eliminate the influence of body size. Performance determinants were obtained from whole-body oxygen consumption, blood sampling, knee-extensor maximal force, muscle oxygenation, wholemuscle morphology, and muscle fiber histochemistry of musculus vastus lateralis. Normalized sprint performance was explained by percentage of fast-type fibers and muscle volume (R 2 = 0.65; P < 0.001) and normalized endurance performance by performance oxygen consumption (Vȯ 2 ), mean corpuscular hemoglobin concentration, and muscle oxygenation (R 2 = 0.92; P < 0.001). Combined sprint and endurance performance was explained by gross efficiency, performance Vȯ 2 , and likely by muscle volume and fascicle length (P = 0.056; P = 0.059). High performance Vȯ 2 related to a high oxidative capacity, high capillarization 3 myoglobin, and small physiologic cross-sectional area (R 2 = 0.67; P < 0.001). Results suggest that fascicle length and capillarization are important targets for training to optimize sprint and endurance performance simultaneously.-Van der Zwaard, S., van der Laarse, W. J., Weide, G., Bloemers, F. W., Hofmijster, M. J., Levels, K., Noordhof, D. A., de Koning, J. J., de Ruiter, C. J., Jaspers, R. T. Critical determinants of combined sprint and endurance performance: an integrative analysis from muscle fiber to the human body. FASEB J. 32, 2110FASEB J. 32, -2123FASEB J. 32, (2018 Many sports require a combination of sprint and endurance performance. During the past decades, physiologic determinants of physical performance have been the subject of intensive investigation (e.g., in cycling, 1-11). Studies focused on determinants of either sprint (e.g., 8-18) or endurance performance (e.g., 1-7, 19-23), even though physical performance is rarely a dichotomous function of only sprint or only endurance. Generally, a limited number of whole-body determinants of sprint or endurance performance have been studied, although there are many physical performance determinants at different levels (i.e., molecular, cellular, whole-muscle, organ, and whole ABBREVIATIONS: 3D, 3-dimensional; CAF, capillaries around the fiber; CD, capillary density; C/F, capillary-to-fiber ratio; FCSA, fiber cross-sectional area; fVȯ 2max , fiber maximal oxygen consumption; [Hb], hemoglobin concentration; Hct, hematocrit; [HHbMb], deoxygenated hemoglobin and myoglobin concentration; iSDH activity, spatially integrated SDH activity, SDH activity 3 FCSA; KE, k...

To cite this Article Hofmijster, Mathijs J. , Landman, Erik H. J. , Smith, Richard M. and Van Soest, A. J. Knoek(2007) 'Effect of stroke rate on the distribution of net mechanical power in rowing', Journal of Sports Sciences, 25: 4,[403][404][405][406][407][408][409][410][411] To link to this Article: DOI: 10.1080/02640410600718046 URL: http://dx.doi.org/10.1080/02640410600718046Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden.The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.Effect of stroke rate on the distribution of net mechanical power in rowing Abstract The aim of this study was to assess the effect of manipulating stroke rate on the distribution of mechanical power in rowing. Two causes of inefficient mechanical energy expenditure were identified in rowing. The ratio between power not lost at the blades and generated mechanical power ( P rower ) and the ratio between power not lost to velocity fluctuations and P rower were used to quantify efficiency (e propelling and e velocity respectively). Subsequently, the fraction of P rower that contributes to the average velocity ( _ x boat ) was calculated (e net ). For nine participants, stroke rate was manipulated between 20 and 36 strokes per minute to examine the effect on the power flow. The data were analysed using a repeated-measures analysis of variance. Results indicated that at higher stroke rates, P rower , _ x boat , e propelling , and e net increase, whereas e velocity decreases (P 5 0.0001). The decrease in e velocity can be explained by a larger impulse exchange between rower and boat. The increase in e propelling can be explained because the work at the blades decreases, which in turn can be explained by a change in blade kinematics. The increase in e net results because the increase in e propelling is higher than the decrease in e velocity . Our results show that the power equation is an adequate conceptual model with which to analyse rowing performance.

Rowers need to combine high sprint and endurance capacities. Muscle morphology largely explains muscle power generating capacity, however, little is known on how muscle morphology relates to rowing performance measures. The aim was to determine how muscle morphology of the vastus lateralis relates to rowing ergometer performance, sprint and endurance capacity of Olympic rowers. Eighteen rowers (12♂, 6♀, who competed at 2016 Olympics) performed an incremental rowing test to obtain maximal oxygen consumption, reflecting endurance capacity. Sprint capacity was assessed by Wingate cycling peak power. M. vastus lateralis morphology (volume, physiological cross-sectional area, fascicle length and pennation angle) was derived from 3-dimensional ultrasound imaging. Thirteen rowers (7♂, 6♀) completed a 2000-m rowing ergometer time trial. Muscle volume largely explained variance in 2000-m rowing performance (R = 0.85), maximal oxygen consumption (R = 0.65), and Wingate peak power (R = 0.82). When normalized for differences in body size, maximal oxygen consumption and Wingate peak power were negatively related in males (r = -0.94). Fascicle length, not physiological cross-sectional area, attributed to normalized peak power. In conclusion, vastus lateralis volume largely explains variance in rowing ergometer performance, sprint and endurance capacity. For a high normalized sprint capacity, athletes may benefit from long fascicles rather than a large physiological cross-sectional area.

It is generally accepted that crew rowing requires perfect synchronization between the movements of the rowers. However, a long-standing and somewhat counterintuitive idea is that out-of-phase crew rowing might have benefits over in-phase (i.e., synchronous) rowing. In synchronous rowing, 5 to 6% of the power produced by the rower(s) is lost to velocity fluctuations of the shell within each rowing cycle. Theoretically, a possible way for crews to increase average boat velocity is to reduce these fluctuations by rowing in antiphase coordination, a strategy in which rowers perfectly alternate their movements. On the other hand, the framework of coordination dynamics explicates that antiphase coordination is less stable than in-phase coordination, which may impede performance gains. Therefore, we compared antiphase to in-phase crew rowing performance in an ergometer experiment. Nine pairs of rowers performed a two-minute maximum effort in-phase and antiphase trial at 36 strokes min−1 on two coupled free-floating ergometers that allowed for power losses to velocity fluctuations. Rower and ergometer kinetics and kinematics were measured during the trials. All nine pairs easily acquired antiphase rowing during the warm-up, while one pair’s coordination briefly switched to in-phase during the maximum effort trial. Although antiphase interpersonal coordination was indeed less accurate and more variable, power production was not negatively affected. Importantly, in antiphase rowing the decreased power loss to velocity fluctuations resulted in more useful power being transferred to the ergometer flywheels. These results imply that antiphase rowing may indeed improve performance, even without any experience with antiphase technique. Furthermore, it demonstrates that although perfectly synchronous coordination may be the most stable, it is not necessarily equated with the most efficient or optimal performance.

BackgroundNear-infrared spectroscopy (NIRS) measurements of oxygenation reflect O2 delivery and utilization in exercising muscle and may improve detection of a critical exercise threshold.PurposeFirst, to detect an oxygenation breakpoint (Δ[O2HbMb-HHbMb]-BP) and compare this breakpoint to ventilatory thresholds during a maximal incremental test across sexes and training status. Second, to assess reproducibility of NIRS signals and exercise thresholds and investigate confounding effects of adipose tissue thickness on NIRS measurements.MethodsForty subjects (10 trained male cyclists, 10 trained female cyclists, 11 endurance trained males and 9 recreationally trained males) performed maximal incremental cycling exercise to determine Δ[O2HbMb-HHbMb]-BP and ventilatory thresholds (VT1 and VT2). Muscle haemoglobin and myoglobin O2 oxygenation ([HHbMb], [O2HbMb], SmO2) was determined in m. vastus lateralis. Δ[O2HbMb-HHbMb]-BP was determined by double linear regression. Trained cyclists performed the maximal incremental test twice to assess reproducibility. Adipose tissue thickness (ATT) was determined by skinfold measurements.ResultsΔ[O2HbMb-HHbMb]-BP was not different from VT1, but only moderately related (r = 0.58–0.63, p<0.001). VT1 was different across sexes and training status, whereas Δ[O2HbMb-HHbMb]-BP differed only across sexes. Reproducibility was high for SmO2 (ICC = 0.69–0.97), Δ[O2HbMb-HHbMb]-BP (ICC = 0.80–0.88) and ventilatory thresholds (ICC = 0.96–0.99). SmO2 at peak exercise and at occlusion were strongly related to adipose tissue thickness (r2 = 0.81, p<0.001; r2 = 0.79, p<0.001). Moreover, ATT was related to asymmetric changes in Δ[HHbMb] and Δ[O2HbMb] during incremental exercise (r = -0.64, p<0.001) and during occlusion (r = -0.50, p<0.05).ConclusionAlthough the oxygenation threshold is reproducible and potentially a suitable exercise threshold, VT1 discriminates better across sexes and training status during maximal stepwise incremental exercise. Continuous-wave NIRS measurements are reproducible, but strongly affected by adipose tissue thickness.