Low Intensity of Running Favors for Anabolic Response after Resistance Exercise

Purpose: Whether active or passive recovery after resistance exercise may affect anabolic and catabolic response is not clear. The aim of this study was to examine the effect of active (moderate or low intensity running) and passive (rest) recovery after resistance exercise on testosterone, cortisol and testosterone/cortisol ratio (T/C) responses. Methods: By counter-balanced design, nine recreationally active males (age: 23.89 ± 0.86 yrs of age; height: 172.89 ± 1.30 cm; weight: 68.37 ± 2.72 kg; VO2max: 56.56 ± 1.70 ml/kg/min) completed three tests including: 65% VO2max running (moderate intensity, RM), 40% VO2max running (low intensity, RL) and passive rest (RR) following 3sets of four resistance exercises (bench press, leg extension, front lat pulldown and leg curl, 12 repetitions at 60%1RM with 2min rest among all sets and exercises). In order to evaluate the systemic anabolic status, we measured plasma testosterone, cortisol and T/C ratio before resistance exercise (baseline), immediately after either active or passive recovery (post), and 30min after recovery (rest). Results: In RM group, T/C was significantly lower (decrease 18.5%, p\u3c.05) than baseline at rest. In RL group, T/C was significantly higher (increase 79.1% at post and increase 123.2% at rest, p\u3c.05) than baseline at post and rest, respectively. At rest, the T/C of RL was higher than RM (RM: 0.49 ± 0.12, RL: 1.08 ± 0.19, p\u3c.05). Conclusions: Resistance exercise and low intensity aerobic exercise is more favorable to enhance anabolic response during post-exercise recovery

Regulation of High-Temperature Stress Response by Small RNAs

Temperature extremes constitute one of the most common environmental stresses that adversely affect the growth and development of plants. Transcriptional regulation of temperature stress responses, particularly involving protein-coding gene networks, has been intensively studied in recent years. High-throughput sequencing technologies enabled the detection of a great number of small RNAs that have been found to change during and following temperature stress. The precise molecular action of some of these has been elucidated in detail. In the present chapter, we summarize the current understanding of small RNA-mediated modulation of high- temperature stress-regulatory pathways including basal stress responses, acclimation, and thermo-memory. We gather evidence that suggests that small RNA network changes, involving multiple upregulated and downregulated small RNAs, balance the trade-off between growth/development and stress responses, in order to ensure successful adaptation. We highlight specific characteristics of small RNA-based tem- perature stress regulation in crop plants. Finally, we explore the perspectives of the use of small RNAs in breeding to improve stress tolerance, which may be relevant for agriculture in the near future

Cigarette Smoking Blunts Exercise-Induced Heart Rate Response among Young Adult Male Smokers

This study aimed to examine the exercise-induced heart rate response (HRR) and heart rate variability (HRV) in subjects caused by inhaling smoke from tobacco cigarettes (TC) and aerosolized vapor from electronic nicotine dispensing systems (ENDS) (commonly referred to as e-cigarettes (EC)). A randomized crossover study recruited 24 young adult male smokers with an average age of 23 years and with a smoking habit of at least two years. Heart rate response was recorded after a maximal multistage shuttle 20 m run test (MMST) under three different levels of nicotine: Control 0 mg nicotine of EC (C), 3 mg nicotine of EC (3EC), and 3 mg nicotine of TC (3TC). HRV was evaluated based on the beat-to-beat time interval during the running test. The results showed no statistically significant differences in the run time to exhaustion under the three conditions (C: 398 ± 151 s; 3EC: 399 ± 160 s; 3TC: 381 ± 150 s). Exercise-induced HRR was significantly attenuated under the TC condition (p < 0.05). Intriguingly, the HRV standard deviation of normal-to-normal intervals (SDNN) during exercise significantly increased under 3EC and 3TC. The results showed that a significant acute autonomic cardiac modulation during exercise is induced by an acute episode of EC and TC smoking

Green tea extract supplementation does not hamper endurance-training adaptation but improves antioxidant capacity in sedentary men

[[abstract]]The purpose of this study was to investigate the effect of green tea extract (GTE) supplementation combined with endurance training on endurance capacity and performance in sedentary men. Forty untrained men (age: 20 ± 1 years) participated in this study. Subjects were assigned to 1 of 4 treatments: (i) placebo-control (CTRL), (ii) GTE, (iii) endurance training (Ex), and (iv) endurance training with GTE (ExGTE). During the 4-week intervention, exercise training was prescribed as 75% oxygen uptake reserve for three 20-min sessions per week, and either GTE (250 mg/day) or placebo was provided. Endurance capacity, malondialdehyde (MDA), total antioxidant status (TAS), and creatine kinase (CK) were examined. Ex and ExGTE but not GTE improved exhaustive-run time (Ex: +8.2%, p = 0.031; ExGTE: +14.3%, p < 0.001); in addition, Ex and ExGTE significantly increased maximal oxygen uptake by ∼14% (p = 0.041) and ∼17% (p = 0.017) above the values of the CTRL group, respectively. Both Ex and ExGTE significantly decreased the increase of CK by ∼11%–32% below that of CTRL following an exhaustive run (Ex: p = 0.007; ExGTE: p = 0.001). Moreover, TAS levels increased by ∼11% in ExGTE after training (p = 0.040), and GTE, Ex, and ExGTE markedly attenuated exercise-induced MDA production (p = 0.01, p = 0.005, p = 0.011, respectively). In conclusion, this investigation demonstrated that daily ingestion of GTE during endurance training does not impair improvements in endurance capacity. Moreover, endurance training combined with GTE not only increases antioxidant capacity without attenuating endurance training adaptations, but also further attenuates acute exercise-induced CK release

The Benefits of Dynamic Core Exercise for Respiratory Muscle Training

[[abstract]]呼吸肌訓練是臨床診斷與醫療廣為採用的方法，呼吸肌功能也是影響運動表現的因素之一，尤其耐力型運動項目。因此除臨床外，呼吸肌訓練逐漸成為提升運動表現的方法，並以特製器材進行。不過，由於呼吸肌位於支撐人體的核心部位，進行核心相關的阻力運動所產生的腹內壓，能刺激橫隔膜達到訓練適應，是一種以非吸吐方式(nonrespiratory maneuver)進行的呼吸肌訓練，且減少特製器材訓練可能引起的不適感。本文針對非吸吐方式訓練呼吸肌的影響，以及相關生理機制，透過資料庫整理相關文獻，歸納以產生65%橫膈壓，利用腹橫肌、腹內斜肌為主的動作，是非吸吐方式刺激呼吸肌，達到最佳訓練效果的處方。 Respiratory muscle training (RMT) is a practice widely applied in the clinical diagnosis and medical fields. Moreover, the respiratory muscle function is also one of the factors affecting sport performance, especially in endurance sports. Thus, RMT conducted using specialized equipment became an effective method to improve performance. However, the body requires a period of adjustment to the training since the respiratory muscle is located near the human core, which leads to induced intra-abdominal pressure that stimulates the diaphragm during core exercises. Alternatively, nonrespiratory maneuvers may reduce the discomfort associated with such training. This paper focuses on the impacts of nonrespiratory maneuvers on RMT and related physiological mechanisms, including a search through databases for similar studies, to conclude that optimal results can be achieved by nonrespiratory RMT when exercises center on the transverse abdominal muscle, internal oblique abdominal muscle to produce a 65% transdiaphragmatic pressure

Systemic Lactate Elevation Induced by Tobacco Smoking during Rest and Exercise Is Not Associated with Nicotine

Lactate is a metabolite produced during anaerobic glycolysis for ATP resynthesis, which accumulates during hypoxia and muscle contraction. Tobacco smoking significantly increases blood lactate. Here we conducted a counter-balanced crossover study to examine whether this effect is associated with inhaling nicotine or burned carbon particles. Fifteen male smokers (aged 23 to 26 years) were randomized into 3 inhalation conditions: tobacco smoking, nicotine vaping, and nicotine-free vaping, conducted two days apart. An electronic thermal evaporator (e-cigarette) was used for vaping. We have observed an increased blood lactate (+62%, main effect: p &lt; 0.01) and a decreased blood glucose (&minus;12%, main effect: p &lt; 0.05) during thermal air inhalations regardless of the content delivered. Exercise-induced lactate accumulation and shuttle run performance were similar for the 3 inhalation conditions. Tobacco smoking slightly increased the resting heart rate above the two vaping conditions (p &lt; 0.05), implicating the role of burned carbon particles on sympathetic stimulation, independent of nicotine and thermal air. The exercise response in the heart rate was similar for the 3 conditions. The results of the study suggest that acute hypoxia was induced by breathing thermal air. This may explain the reciprocal increases in lactate and decreases in glucose. The impaired lung function in oxygen delivery of tobacco smoking is unrelated to nicotine

Effects of Different Resistance Exercise and Occlusion Pressures on Metabolic Stress and Anabolic Hormonal Responses after Exercise

[[abstract]]本研究目的在探討單次不同阻力運動搭配不同加壓負荷對運動後代謝壓力與合成激素反應的影響。本研究招募15名健康男性，依對抗平衡次序原則分為：一、高強度阻力（70% 1 RM [repetition maximum]）；二、低強度阻力（40% 1 RM）；三、高強度阻力／低加壓（70% 1 RM + 70% SBP [systolic blood pressure]）；四、低強度阻力／高加壓（40% 1 RM+130% SBP）與五、低強度阻力／低加壓（40% 1 RM+70% SBP），間隔為五日。採雙腿斜坐推蹬方式（5組、12次），運動時加壓於雙腿大腿近端。比較運動前、運動後立即、15、30、60分鐘時，血清生長激素與睪固酮、乳酸與自覺努力程度之差異；並比較運動前與運動後60分鐘對肌力之影響。研究結果顯示：高強度阻力／低加壓的模式在運動後有較高的生長激素且持續至運動後30分鐘；相較於低強度阻力下的各種模式，高強度阻力／低加壓的模式在運動後立即有較高的睪固酮濃度，且能在運動後引起較高的壓力反應（乳酸與RPE值）並降低最大等長肌力表現，以及增加肌纖維徵召。本研究結論：高強度阻力運動搭配低加壓壓力的運動模式可顯著提高體內代謝壓力，同時可刺激更多生長激素與睪固酮分泌，對肌肉組織合成作用具有正面效益。 The purpose of this study was to investigate the effects of different resistance loads (70% and 40% 1 RM [repetition maximum]) combined with different occlusion pressures (130% and 70% SBP [systolic blood pressure]) on metabolic stress and anabolic hormonal response after exercise. Fifteen healthy males voluntarily participated in this study. A counter-balance order experimental design was used in this investigation. On the experiment day, each subject performed a single bout of bilateral leg extension (5 sets, 12 repetitions with 1 min rest for each set) under the following five experimental conditions: (1) high intensity resistance exercise (HR, 70% 1 RM), (2) low intensity resistance exercise (LR, 40% 1 RM), (3) HR with low occlusion pressure (HRLO, 70% 1 RM + 70% SBP), (4) LR with high occlusion pressure (LRHO, 40% 1 RM+130% SBP), and (5) LR with low occlusion pressure (LRLO, 40% 1 RM+70% SBP). Blood biomarkers (i.e. hormones and lactate) were measured at prior to exercise (pre), and 0, 15, 30, 60 min after (post) exercise. The maximal isometric strength and electromyography of vastus lateralis were compared at pre and post-60. Results indicated that the GH of HRLO was higher at post-0, post-15 and post-30 than that at pre-exercise. The testosterone of HRLO was higher at post compared to LRHO, LRLO and LR. Furthermore, HRLO induced greater metabolic and physiological stress responses (LA and RPE) and a greater decline of muscular strength with more muscle fiber recruitment. We concluded that high intensity resistance exercise combined with low occlusion pressure would elevate metabolic stress and reduce maximal strength performance, thereby stimulating higher GH and testosterone responses. Our results thus suggest that this exercise model would have the positive benefits on muscle anabolic effect