The Journal of Physical Fitness and Sports Medicine
Online ISSN : 2186-8123
Print ISSN : 2186-8131
ISSN-L : 2186-8131
10 巻, 1 号
選択された号の論文の7件中1~7を表示しています
Review Article
  • Kenneth Vitale, Shawn Hueglin
    2021 年 10 巻 1 号 p. 1-11
    発行日: 2021/01/25
    公開日: 2021/01/13
    ジャーナル オープンアクセス

    Interest in vegetarian and vegan diets continues to grow, not only in the general population, but in the high-performing athlete. Vegetarian diets may lower risk of chronic diseases and have proposed ergogenic benefits to the athlete regarding exercise performance and enhanced recovery. However, controversy and confusion exist in the literature regarding vegetarianism. Traditionally, a vegetarian or vegan diet was considered low in certain micronutrients (iron, zinc, calcium, iodine, vitamin A, B2, B12, D), as well as protein, omega-3 fatty acids, and total energy needs. However, a vegetarian diet typically contains higher complex carbohydrates, dietary fiber, magnesium, nitrates, folic acid, vitamin C and E, carotenoids and other phytochemicals which may offer certain performance benefits to the athlete. This review summarizes the current literature on the benefits of a vegetarian diet specific to the athlete, clarifies nutritional requirements, and provides insight on the potential performance benefits. With proper meal planning, an athlete can meet all their nutritional needs with foods derived from plants without any loss in physical performance.

Regular Article
  • Tomoya Ishii, Syusaku Sasada, Shinya Suzuki, Tomoyoshi Komiyama
    2021 年 10 巻 1 号 p. 13-23
    発行日: 2021/01/25
    公開日: 2021/01/13
    ジャーナル オープンアクセス

    Surface electromyographic activity (sEMG) of the biceps brachii (BB) during weak elbow flexion has been reported to immediately increase after strong elbow flexion even while exerting consistent force; this phenomenon is called “post-contraction potentiation” (PCP). To determine whether the central nervous system is involved in PCP, we investigated the effect of transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) during PCP. Initially, the participants were instructed to perform successive muscle contraction tasks with different forces: 2% (Test 1); then 25%, 50%, or 100% (conditioning contraction [CC]); and again 2% (Test 2) of maximum voluntary contraction (MVC). In subsequent experiments, the CC intensity was set at 50% MVC, and tDCS (anodal, cathodal, and sham) was applied to the M1 before the task. In the last experiment, TMS was applied to M1 to evaluate the excitability of the corticospinal tract during Tests 1 and 2. The CC intensity at 50% or 100% MVC generated PCP, but didn’t at 25% MVC. Anodal tDCS significantly decreased the magnitude of PCP, while cathodal tDCS showed an increase in magnitude compared to sham tDCS. The BB motor-evoked potential amplitude during Test 2 was lower compared to that during Test 1. These findings suggest that changes in the excitability of the corticospinal tract and resultant changes in the activation pattern of motor unit activity play a role in generating PCP.

  • Rika Kimoto, Isao Kambayashi, Akane Akizuki, Miku Tsukamoto, Munem ...
    2021 年 10 巻 1 号 p. 25-32
    発行日: 2021/01/25
    公開日: 2021/01/13
    ジャーナル オープンアクセス

    The autonomic nervous system (ANS) maintains homeostasis through the balance of the sympathetic and parasympathetic subsystems or divisions. Currently, analysis of heart rate variability (HRV) offers an indirect, non-invasive assessment of ANS function. An irregular lifestyle and stress are known to affect ANS balance, influencing many diseases. Moreover, ANS disorder plays an important role in climacteric symptoms in menopausal females. The purpose of this study was designed to assess the effects of yoga practice sessions (herein referred to as “yoga”) on ANS function and focused on the relationship between ANS function and subject age or personal history of yoga. A total of 113 healthy females participated in this study. They attended a 90-120 minute yoga practice session conducted by a well-qualified instructor. ANS function was assessed before and after the yoga practice session by HRV power spectral analysis. As a result, in females, yoga reduced fatigue by primarily improving sympathetic activity. In addition, the LnHF values tended to be increased after yoga only in the over-60y (60 years) group. Furthermore, there were individual differences in the amount of change in the sympathetic and parasympathetic activity values. In females with a low activity level before yoga, values were increased; whereas values decreased in females with a high activity value before yoga. In subjects with ≥5-year history of yoga, there was no significant correlation between the ANS parameters and subject age. Our study suggests that yoga for females supports well-balanced ANS function, and that the continuation of yoga over a period of time contributes to an improvement in ANS function.

  • Jumpei Osakabe, Toshiyuki Ohya, Jun Koizumi, Ryosuke Inada, Takaak ...
    2021 年 10 巻 1 号 p. 33-37
    発行日: 2021/01/25
    公開日: 2021/01/13
    ジャーナル オープンアクセス

    Inspiratory muscle fatigue (IMF) may limit exercise performance. It has been reported that IMF occurs after various exercises; however, it remains unclear whether IMF occurs after tennis singles match play. The purpose of this study was to test whether tennis singles match play induced IMF. Nine female college tennis players participated in this study. The players were paired in accordance with their skill level, and then played a singles match for an effective playing time (EPT) of 20 minutes. A portable autospirometer was used to measure the maximal inspiratory pressure (MIP) before and immediately after the match as an index of IMF. Heart rate and perceptual measurements were recorded after every 2.5 minutes of effective playing time. The total match duration in this study was 96 ± 8 minutes. Post-match MIP was significantly lower than pre-match MIP (103 ± 21 cmH2O vs. 92 ± 22 cmH2O, p < 0.05, effect size = 0.47), and the magnitude of the decrease in MIP was 10.0 ± 9.7%. The present results show that IMF occurs after tennis singles match play in females.

  • Ryota Sone, Kenji Yamamoto, Kenji Ohishi
    2021 年 10 巻 1 号 p. 39-44
    発行日: 2021/01/25
    公開日: 2021/01/13
    ジャーナル オープンアクセス

    In various sports, high-intensity training reduces the oral immune function of the player. The effect of volleyball training camp on salivary immune function is unclear. This study aimed to investigate the effect of pre-season training on salivary immune function in elite collegiate volleyball players. Twenty-one elite collegiate volleyball players (mean age: 19.6 ± 1.1 years, mean height: 185.2 ± 7.8 cm) participated in this observational study. Saliva samples were taken on Day-1 (First day) and Day-11 (Final day) during pre-season training camp. Fatigue was measured using a VAS (visual analog scale) every day during the training camp period. Oral immune function was assessed in terms of secretory immunoglobulin A (s-SIgA) secretion rate and nitric oxide (s-NO) secretion rate. The s-NO secretion rate showed no significant change from Day-1 (0.69 ± 0.49 µmol/min) to Day-11 (0.56 ± 0.33 µmol/min). However, the s-SIgA secretion rate on Day-11 (28 ± 16 µg/min) was significantly lower (P < 0.05) than that on Day-1 (35 ± 18 µg/min). Changes in fatigue scale scores positively correlated with changes in s-NO secretion rate (rs = .591, P < 0.01), but not with changes in s-SIgA secretion rate (rs = .411, P = 0.06). In this study, the concentration of s-NO stored frozen was determined, but the effect of the storage method on s-NO should be investigated in future studies. In conclusion, pre-season volleyball training camp may affect oral immune function as in other sports.

Short Communication
  • Takeru Shima, Subrina Jesmin, Hayato Nakao, Kentaro Tai, Tomonori ...
    2021 年 10 巻 1 号 p. 45-49
    発行日: 2021/01/25
    公開日: 2021/01/13
    ジャーナル オープンアクセス

    Empathy, which consists of cognitive and affective empathy, is one of the vital skills in humans for creating and maintaining relationships with others, now, there are many empathy-deficient people, possibly deriving from an increase in harassment-related issues. Although there is a possibility that physical activity improves empathy, the association of physical activity with cognitive and affective empathy in healthy humans remains unclear. Thus, the present study aims to clarify the relationship between levels of physical activity and self-reported empathy. Eight hundred and ninety-three responses for two questionnaires, the short version of the International Physical Activity Questionnaire (SV-IPAQ) and Questionnaire of Cognitive and Affective Empathy (QCAE), were analyzed. Levels of physical activity in a usual week were measured based on the SV-IPAQ, and participants were divided into three groups: low, moderate and high physical activity. The scores for cognitive and affective empathy were measured based on QCAE. We found that people with a moderate or high physical activity level show significantly higher self-reported cognitive empathy compared to people with a low physical activity level. The score for self-reported affective empathy wasn’t affected by physical activity level. Physical activity level in a usual week showed a significant positive correlation with self-reported cognitive empathy scores, but not with self-reported affective empathy scores. Our findings imply that an increase in physical activity contributes to better cognitive empathy in healthy young adults.

  • Hiroto Honda, Makoto Igaki, Motoaki Komatsu, Shin-ichiro Tanaka, T ...
    2021 年 10 巻 1 号 p. 51-56
    発行日: 2021/01/25
    公開日: 2021/01/13
    ジャーナル オープンアクセス

    We aimed at evaluating the effect of short-duration stair climbing–descending exercise (ST-EX) on 24-hour blood glucose (BG) response in people with type 2 diabetes (T2D). Seven men (age, 70.1 ± 1.3 years) with uncomplicated T2D consumed three meals per day according to a meal plan for patients with diabetes. Participants completed one session of ST-EX 60 and 120 min after each meal on the first day (ST-EX day), and did not perform ST-EX on the following day (REST day). Each ST-EX session comprised two 3-min bouts of brisk climbing to the second floor, followed by walking down to the first floor. The BG levels on the experimental days were recorded using a continuous glucose monitoring device. The mean BG level and the area under the curve for BG in the 24-hour period on the ST-EX day were significantly lower than those in the same period on the REST day (both p < 0.05). The duration of hyperglycemia (BG > 10 mmol/L) on the ST-EX day was significantly shorter than that on the REST day (p < 0.05). Repeated 3-min ST-EX after each meal might be an effective strategy to improve 24-hour glucose excursions in people with T2D.

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