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Background Olympic rowing relies heavily on aerobic metabolism, but the demands on strength and power have not yet been thoroughly investigated (Lawton et al., 2011). As the characteristic pacing strategy compounds an initial start sprint, a sustained middle section and end spurt, the neuromuscular and physiological requirements of the particular phases need to be considered more closely (Garland, 2005; Mikulic, 2011). Therefore, the purpose of this study was to identify strength qualities for distinct phases in rowing performance in adolescent athletes. Methods The cross-sectional analysis of fourteen national competitive rowing athletes (4 female; 10 male) included anthropometrics, isometric and isokinetic leg press, back extension and flexion, isometric mid-thigh pull (MTP) and handgrip strength, VO2max, and a 2000 m time trial, in which peak forces were measured in the start, middle and end phase. The rate of force developments (RFD) were obtained for isometric leg press (150 and 350 ms) and MTP (150 ms and 300 ms). Stepwise regression models were created for ergometer performance in the start, middle and end phases. Results The best fit model for the start phase included isometric back extension and RFD 300 ms of MTP (R2 = 0.912, p < 0.001), while for the middle section it were VO2max, isometric leg press and sitting height (R2 = 0.844, p < 0.001). For the end phase a best fit was observed for isometric back flexion, RFD 350 ms of leg press, body height and sex (R2 = 0.965 p < 0.001), whereas absolute VO2max, isokinetic back flexion and sex explained variance over the entire 2000 m time trial (R2 = 0.975, p < 0.001). Conclusion For the high acceleration at the start, force transmission through maximum back strength seems to be essential, while fast power production along the kinetic chain is also relevant (Baudouin & Hawkins, 2002). In addition to VO2max, produced maximum strength in the leg press explains the importance for the force production of the sustained middle section (Cosgrove et al., 1999). These results indicate that maximal force complements the reliance on VO2max, as well as neuromuscular parameters and maximal force transmission seems to be important for the start phase. Further research through intervention studies is needed to refine training recommendations. References Baudouin, A., & Hawkins, D. (2002). A biomechanical review of factors affecting rowing performance. British Journal of Sports Medicine, 36(6), 396-402. http://dx.doi.org/10.1136/bjsm.36.6.396 Cosgrove, M. J., Wilson, J., Watt, D., Grant, S. F. (1999). The relationship between selected physiological variables of rowers and rowing performance as determined by a 2000 m ergometer test. Journal of Sports Sciences, 17(11), 845-852. https://doi.org/10.1080/026404199365407 Garland, S. (2005). An analysis of the pacing strategy adopted by elite competitors in 2000 m rowing. British Journal of Sports Medicine, 39(1), 39-42. https://doi.org/10.1136/bjsm.2003.010801 Lawton, T. W., Cronin, J. B., & McGuigan, M. R. (2011). Strength testing and training of rowers: A review. Sports Medicine, 41(5), 413-432. https://doi.org/10.2165/11588540-000000000-00000 Mikulic, P. (2011). Maturation to elite status: A six-year physiological case study of a world champion rowing crew. European Journal of Applied Physiology, 111(9), 2363-2368. https://doi.org/10.1007/s00421-011-1870-y

Background Isomaltulose has been discussed as a low glycaemic carbohydrate but evidence concerning performance benefits and physiological responses has produced varying results. Therefore, we primarily aimed to investigate the effects of isomaltulose ingestion compared to glucose and maltodextrin on fat and carbohydrate oxidation rates, blood glucose levels and serum hormone concentrations of insulin and glucose-dependent insulinotropic polypeptide (GIP). As secondary aims, we assessed running performance and gastrointestinal discomfort. Methods Twenty-one male recreational endurance runners performed a 70-min constant load trial at 70% maximal running speed (Vmax), followed by a time to exhaustion (TTE) test at 85% Vmax after ingesting either 50 g isomaltulose, maltodextrin or glucose. Fat and carbohydrate oxidation rates were calculated from spiroergometric data. Venous blood samples for measurement of GIP and insulin were drawn before, after the constant load trial and after the TTE. Capillary blood samples for glucose concentrations and subjective feeling of gastrointestinal discomfort were collected every 10 min during the constant load trial. Results No between-condition differences were observed in the area under the curve analysis of fat (p = 0.576) and carbohydrate oxidation rates (p = 0.887). Isomaltulose ingestion led to lower baseline postprandial concentrations of blood glucose compared to maltodextrin (percent change [95% confidence interval], − 16.7% [− 21.8,-11.6], p < 0.001) and glucose (− 11.5% [− 17.3,-5.7], p = 0.001). Similarly, insulin and GIP concentrations were also lower following isomaltulose ingestion compared to maltodextrin (− 40.3% [− 50.5,-30.0], p = 0.001 and − 69.1% [− 74.3,-63.8], p < 0.001, respectively) and glucose (− 32.6% [− 43.9,-21.2], p = 0.012 and − 55.8% [− 70.7,-40.9], p < 0.001, respectively). Furthermore, glucose fluctuation was lower after isomaltulose ingestion compared to maltodextrin (− 26.0% [− 34.2,-17.8], p < 0.001) and glucose (− 17.4% [− 29.1,-5.6], p < 0.001). However, during and after exercise, no between-condition differences for glucose (p = 0.872), insulin (p = 0.503) and GIP (p = 0.244) were observed. No between-condition differences were found for TTE (p = 0.876) or gastrointestinal discomfort (p = 0.119). Conclusion Isomaltulose ingestion led to lower baseline postprandial concentrations of glucose, insulin and GIP compared to maltodextrin and glucose. Consequently, blood glucose fluctuations were lower during treadmill running after isomaltulose ingestion, while no between-condition differences were observed for CHO and fat oxidation rates, treadmill running performance and gastrointestinal discomfort. Further research is required to provide specific guidelines on supplementing isomaltulose in performance and health settings.

Seipp, D, Feuerbacher, JF, Jacobs, MW, Dragutinovic, B, and Schumann, M. Acute effects of high-intensity interval running on lower-body and upper-body explosive strength and throwing velocity in handball players. J Strength Cond Res 36(11): 3167–3172, 2022—The purpose of this study was to determine the acute effects of handball-specific high-intensity interval training (HIIT) on explosive strength and throwing velocity, after varying periods of recovery. Fourteen highly trained male handball players (age: 25.4 (26.2 ± 4.2) performed HIIT consisting of repeated 15-second shuttle runs at 90% of final running speed (VIFT) to exhaustion. Upper-body and lower-body explosive strength and throwing velocities were measured before and immediately after HIIT, as well as after 6 hours. These tests included 3 repetitions of both bench press and squat exercise at 60% of the 1 repetition maximum (1RM) as well as 3 repetitions of the set shot without run up and jump shot, respectively. Explosive squat performance was significantly reduced at post (−5.48%, p = 0.026) but not at 6 h (−0.24%, p = 1.000). Explosive bench press performance remained statistically unaltered at post (0.32%, p = 1.000) and at 6 hour (1.96%, p = 1.000). This was also observed in the subsequent throws both immediately after (−0.60%, p = 1.000) (−0.31%, p = 1.000) and at 6 h (−1.58%, p = 1.000) (1.51%, p = 0.647). Our data show a reduction in explosive strength of the lower but not upper extremities when preceded by running HIIT. Since throwing velocity was not affected by intense lower-body exercise, combining lower-body HIIT and throwing practice may be of no concern in highly trained handball players.

Aerobic metabolism dominates Olympic rowing, but research on the relative contribution of strength and power demands is limited. This study aimed to identify the contribution of different strength determinants for distinct phases of rowing ergometer performance. The crosssectional analysis comprised of 14 rowing athletes (4 female, 10 male, age: 18.8 ± 3.0y, 16.9 ± 2.2y). Measurements included anthropometrics, maximal strength of leg press, trunk extension and flexion, mid-thigh pull (MTP) and handgrip strength, VO 2 max, and a 2000 m time trial, where peak forces at the start, middle and end phase were assessed. Additionally, rate of force development (RFD) was assessed during the isometric leg press and MTP with intervals of 150, 350 ms and 150, 300 ms, respectively. Stepwise regression models for ergometer performance showed that the start phase was mainly explained by maximal trunk extension and RFD 300 ms of MTP (R 2 = 0.91, p < 0.001) and the middle section by VO 2 max, maximal leg press strength and sitting height (R 2 = 0.84, p < 0.001). For the end phase, a best fit was observed for trunk flexion, RFD 350 ms of leg press, body height and sex (R 2 = 0.97 p < 0.001), whereas absolute VO 2 max, trunk flexion and sex explained variance over the entire 2000 m time trial (R 2 = 0.98, p < 0.001). It appears that for the high acceleration in the start phase, force transmission through maximum strength for trunk extension is essential, while fast power production along the kinetic chain is also relevant. Additionally, the results support that maximal force complements the reliance on VO 2 max. Further intervention studies are needed to refine training recommendations.