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Acute Beetroot Juice Supplementation Has No Effect on Upper- and Lower-Body Maximal Isokinetic Strength and Muscular Endurance in International-Level Male Gymnasts

Ozcan Esen, Joseph Fox, Raci Karayigit, and Ian Walshe

Nitrate ( NO 3 ) has properties that can improve muscle function, leading to improvements in metabolic cost of exercise as well as enhance force production. Gymnastics is a whole-body sport, involving events that demand a high level of strength and fatigue resistance. However, the effect of NO 3 supplementation on both upper- and lower-body function in gymnasts is unknown. This study examined the effect of acute beetroot juice (BRJ) supplementation on isokinetic strength and endurance of the upper- and lower-body in highly trained international-level male gymnasts. In a double-blind, randomized crossover design, 10 international-level male gymnasts completed two acute supplementation periods, consuming either 2 × 70 ml NO 3 -rich (∼12.8 mmol/L of NO 3 ) or NO 3 -depleted (PLA) BRJ. Maximal strength of the upper-leg and upper-arm at 60°/s, 120°/s, 180°/s, and 300°/s, and muscular endurance (50 repeated isokinetic contractions at 180°/s) were assessed. Plasma NO 3 (BRJ: 663 ± 164 μM, PLA: 89 ± 48 μM) and nitrite ( NO 2 ) concentrations (BRJ: 410 ± 137 nmol/L, PLA: 125 ± 36 nmol/L) were elevated following BRJ compared to PLA (both p < .001). Maximal strength of knee and elbow extensors and flexors did not differ between supplements (p > .05 for all velocities). Similarly, fatigue index of knee and elbow extension and flexion was not different between supplements (all p > .05). Acute BRJ supplementation, containing ∼12.8 mmol/L of NO 3 , increased plasma NO 3 and NO 2 concentrations, but did not enhance isokinetic strength or fatigue resistance of either upper or lower extremities in international-level male gymnasts.

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Combining Heat and Altitude Training to Enhance Temperate, Sea-Level Performance

Olivier Girard, Peter Peeling, Sébastien Racinais, and Julien D. Périard

Background: Repeated exposure to heat (ie, plasma volume expansion) or altitude (ie, increase in total hemoglobin mass), in conjunction with exercise, induces hematological adaptations that enhance endurance performance in each respective environment. Recently, combining heat and altitude training has become increasingly common for athletes preparing to compete in temperate, sea-level conditions. Purpose: To review the physiological adaptations to training interventions combining thermal and hypoxic stimuli and summarize the implications for temperate, sea-level performance. Current Evidence: To date, research on combining heat and hypoxia has employed 2 main approaches: simultaneously combining the stressors during training or concurrently training in the heat and sleeping at altitude, sometimes with additional training in hypoxia. When environmental stimuli are combined in a training session, improvements in aerobic fitness and time-trial performance in temperate, sea-level conditions are generally similar in magnitude to those observed with heat, or altitude, training alone. Similarly, training in the heat and sleeping at altitude does not appear to provide any additional hematological or nonhematological benefits for temperate; sea-level performance relative to training in hot, hypoxic, or control conditions. Conclusions: Current research regarding combined heat and altitude interventions does not seem to indicate that it enhances temperate, sea-level performance to a greater extent than “traditional” (heat or hypoxia alone) training approaches. A major challenge in implementing combined-stressor approaches lies in the uncertainty surrounding the prescription of dosing regimens (ie, exercise and environmental stress). The potential benefits of conducting heat and altitude exposure sequentially (ie, one after the other) warrants further investigation.

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Effects of In-Exercise Carbohydrate Supplementation on Prolonged High-Intensity Exercise Performance in Oral Contraceptive Users

Serene J.L. Lee, Fleur E.C.A. Van Rens, and Jeremiah J. Peiffer

Purpose: To examine the impact of oral contraceptive (OC) phases on performance, physiological, and subjective responses to prolonged, intensive exercise when carbohydrate (CHO) stores are reduced. Methods: Ten well-trained female cyclists using monophasic OC completed 4 identical trials (>150 min) under conditions of in-trial 60-g·h−1 CHO supplementation (CHO+) or placebo (CHO−) during the sugar- (SUG) and active-pill (ACT) phases of their OC cycle. Each trial comprised two 400-kcal time trials (TT) separated by 1 hour of submaximal cycling at first ventilatory threshold. Results: Change in completion time from TT1 to TT2 was minimized in CHO+ compared with CHO− (4.06 [2.55] vs 6.08 [5.33] min; P = .019, effect size = −0.36). An interaction effect of OC and CHO was observed for time to complete TT (P = .006), mean TT power (P = .002), mean TT heart rate (P = .002), and posttrial emotional balance (P = .020) and negative emotional state (P = .033). In ACT, mean TT power and heart rate were higher in CHO+ when compared with CHO−, resulting in faster TTs in CHO+ and improved posttrial emotional well-being. When CHO was not supplemented, TT power and heart rate were higher in SUG when compared with ACT, resulting in faster TTs in SUG and improved posttrial emotional balance. Conclusion: CHO depletion during ACT negatively influenced TT performance and emotional well-being when compared with SUG. Irrespective of OC pill phase, CHO supplementation should be prioritized to sustain performance and improve postexercise recovery–stress balance.

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From Mentorship to Sponsorship in Sport Science

Iñigo Mujika and Peter Leo

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Individualizing Basketball-Specific Interval Training Using Anaerobic Speed Reserve: Effects on Physiological and Hormonal Adaptations

Chenhang Wang and Mingliang Ye

Purpose : We compared the adaptive responses to supramaximal high-intensity interval training (HIIT) individualized according to anaerobic speed reserve (ASR), the 30-15 Intermittent Fitness Test (V IFT), and velocity associated with maximum oxygen uptake (MAS) to determine which approach facilitates more identical adaptations across athletes with different profiles. Methods : Thirty national-level basketball players (age = 28.4 [5] y; body mass = 88.9 [6.3] kg; height = 190 [4.8] cm) were randomly assigned to 3 training groups performing 2 sets of 4, 6, 8, 6, 8, and 10-minute runs (from first to sixth week, respectively), consisting of 15-second running at Δ%20ASR (MAS + 0.2 × ASR), 95%V IFT, and 120%MAS, with 15 seconds recovery between efforts and a 3-minute relief between sets. Results : All 3 interval interventions significantly (P < .05) enhanced maximum oxygen uptake ( V ˙ O 2 max ), oxygen pulse ( V ˙ O 2 / HR ), first and second ventilatory threshold (VT1 and VT2), cardiac output ( Q ˙ max ), stroke volume, peak and average power output, testosterone levels, and testosterone-to-cortisol ratio following the training period. Different values of interindividual variability (coefficient of variation) for the percentage changes of the measured variables were observed in response to HIITASR, HIITv IFT, and HIITMAS for V ˙ O 2 max (8.7%, 18.8%, 34.6%, respectively), V ˙ O 2 / HR (9.5%, 15.0%, 28.6%), VT1 (9.6%, 19.6%, 34.6%), VT2 (21.8%, 32.4%, 56.7%), Q ˙ max (8.2%, 16.9%, 28.8%), stroke volume (7.9%, 15.2%, 23.5%), peak power output (20%, 22%, 37.3%), average power output (21.1%, 21.3%, 32.5%), testosterone (52.9%, 61.6%, 59.9%), and testosterone-to-cortisol ratio (55.1%, 59.5%, 57.8%). Conclusions : Supramaximal HIIT performed at Δ%20ASR resulted in more uniform physiological adaptations than HIIT interventions prescribed using V IFT or MAS. Although hormonal changes do not follow this approach, all the approaches induced an anabolic effect.

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The Nature of Sports Coach Development in China: What Are We Trying to Achieve?

Shiyang Li, Howie J. Carson, and Dave Collins

Coach education and continuing career development have become a significant focus of global discussion within the sport domain. Current mainstream strategies for developing and assessing coaches in most countries, including China, are based on competency-based systems. However, there are many shortcomings of this system, especially when considering the varied practical challenges and needs of coaches and athletes; in short, such an approach does not facilitate enough adaptability. The purpose of this article is to critically review the literature, exploring both competence- and expertise-based coach development systems and their implications for coaching practice in China. First, we introduce and discuss the competency-based approach, including its strengths and weaknesses and how this applies within the Chinese development system. Next, we introduce and evaluate an alternative, expertise-based development system characterized by adaptability and greater inclusiveness within the coaching domain, which is underpinned by a distinct set of cognitive decision-making skills from the coach’s perspective. In addition, we expand this discussion by explaining the implications of this approach for coach assessment and offer some future suggestions for research in this area.

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What Is Known About Mindfulness and Self-Compassion Among Sport Coaches? A Scoping Review

Karin Hägglund, Göran Kenttä, Christopher R.D. Wagstaff, and Marte Bentzen

Mindfulness and self-compassion are two constructs positively related to well-being and mental health outside sport. Within sport, these constructs are emerging in research, yet the extant work has primarily been conducted with athlete samples. The aim of this scoping review was to provide a broad synthesis of the literature on mindfulness and self-compassion among coaches. Fourteen articles were included, 11 of them published 2019–2022. Of the 14 publications, the concepts studied were mindfulness (n = 10), self-compassion (n = 2), and a combination of both (n = 2). The samples were predominantly male coaches (68.7%), and most of the studies targeted coaches at the elite or competitive level. The most common area studied was developing and testing interventions and programs, followed by depicting relationships of mindfulness or self-compassion with desirable outcomes. This review significantly extends the current knowledge by illuminating critical issues in this rapidly moving area of research; the need for conceptual and contextual clarity of mindfulness and self-compassion; methodological considerations, such as measures that may allow reliable comparison across studies; and the need to further explore the potential benefits of mindfulness and self-compassion for coaches for sustainability and performance.

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Why Should Athletes Brake Fast? Influence of Eccentric Velocity on Concentric Performance During Countermovement Jumps at Different Loads

Jose L. Hernández-Davó, Rafael Sabido, Manuel Omar-García, and Daniel Boullosa

Purpose: The aim of the present study was to analyze the effect of different eccentric tempos on eccentric kinetics and kinematics and the subsequent concentric performance when performing countermovement jumps against different loads. Methods: After 1-repetition-maximum assessment and 2 familiarization sessions, 13 well-trained participants performed, in randomized order, 12 sets (4 tempos × 3 loads) of 4 repetitions of the loaded countermovement-jump exercise. The eccentric tempos analyzed were 5 and 2 seconds, as fast as possible, and accelerated (ie, without pause between repetitions), while the loads used were 30%, 50%, and 70% of 1-repetition maximum. Several kinetic and kinematic variables during both phases were recorded by linking a linear position transducer to the barbell. Results: The eccentric work was greater in the accelerated condition despite no changes in the eccentric depth. The peak and mean propulsive velocities were greater in the as-fast-as-possible and accelerated conditions. Correlation analysis showed that, compared with the 5-second condition, the increased concentric performance in the accelerated condition was related to the difference in eccentric work performed in the last 100 milliseconds of the eccentric phase (r > .770). Conclusions: Contrary to current practices, the current study highlights the need for performing the eccentric phase of loaded countermovement jumps, a common exercise performed by athletes for both training and evaluation purposes, as fast as possible. This allows not only a greater eccentric work but also improved concentric performance.

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Characteristics of Physical Activity Interventions for People With Visual Impairments: A Scoping Review

Soyoung Choi and JJ Pionke

This study evaluated physical activity interventions designed for individuals with visual impairments and sought to guide health intervention scientists aiming to promote physical activity in this demographic. We delved into the specifics of participants’ visual impairments, intervention features, accommodation approaches, and replicability prospects. The search spanned four databases, namely PubMed, CINAHL, SportDiscus, and Scopus, providing a wide scope and diversity of potential studies. There were no restrictions on publication years. We reviewed 13 studies, totaling 15 interventions. A consensus on visual-impairment definitions remains elusive, and the intervention dosages displayed variability. Notably, 66.7% (n = 7) integrated behavior-change techniques to amplify physical activity levels. Multiple studies employed audio descriptions as an accommodation method. While most studies provided adequate information for potential replication, detailed study protocols were frequently absent. It is essential for developed interventions to be persistently evaluated and fine-tuned to optimize results.

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Effects of High-Intensity Inspiratory Muscle Warm-Up on High-Intensity Exercise Performance and Muscle Oxygenation

Jun Koizumi and Toshiyuki Ohya

Purpose: An inspiratory muscle warm-up (IMW) improves inspiratory muscle function, but the effects of high-intensity exercise are inconsistent. We aimed to determine the effects of high-intensity IMW on high-intensity exercise performance and muscle oxygenation. Methods: Ten healthy men (maximal oxygen uptake [ V ˙ O 2 max ] 52.2 [5.0] mL·kg–1·min–1) performed constant-load exercise to exhaustion on a cycle ergometer at V ˙ O 2 max under 2 IMW conditions: a placebo condition (PLA) and a high-intensity IMW condition (HIGH). The inspiratory loads were set at 15% and 80% of maximal inspiratory pressure, respectively. Maximal inspiratory pressure was measured before and after IMW. Oxyhemoglobin was measured in the vastus lateralis by near-infrared spectroscopy during exercise. Rating of perceived exertion (RPE) for a leg was measured after 1 and 2 minutes of exercise. Results: Exercise tolerance was significantly higher under HIGH than PLA (228 [49] s vs 218 [49] s, P = .003). Maximal inspiratory pressure was significantly increased by IMW under HIGH (from 125 [20] to 136 [25] cm H2O, P = .031). Oxyhemoglobin was significantly higher under HIGH than PLA at 80% of the total duration of exercise (P = .048). RPE for the leg was significantly lower under HIGH than PLA after 2 minutes of exercise (P = .019). Conclusions: Given that oxyhemoglobin is an index of local oxygen supply, the results of this study suggest that high-intensity IMW increases the oxygen supply to active limbs. It may also reflect a reduction in RPE in the leg. In addition, high-intensity IMW may improve exercise performance.