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Smilios, I, Myrkos, A, Zafeiridis, A, Toubekis, A, Spassis, A, and Tokmakidis, SP. The effects of recovery duration during high-intensity interval exercise on time spent at high rates of oxygen consumption, oxygen kinetics, and blood lactate. J Strength Cond Res 32(8): 2183-2189, 2018-The recovery duration and the work-to-recovery ratio are important aspects to consider when designing a high-intensity aerobic interval exercise (HIIE). This study examined the effects of recovery duration on total exercise time performed above 80, 90, and 95% of maximum oxygen consumption (V[Combining Dot Above]O2max) and heart rate (HRmax) during a single-bout HIIE. We also evaluated the effects on V[Combining Dot Above]O2 and HR kinetics, blood lactate concentration, and rating of perceived exertion (RPE). Eleven moderately trained men (22.1 ± 1 year) executed, on 3 separate sessions, 4 × 4-minute runs at 90% of maximal aerobic velocity (MAV) with 2, 3, and 4 minutes of active recovery. Recovery duration did not affect the percentage of V[Combining Dot Above]O2max attained and the total exercise time above 80, 90, and 95% of V[Combining Dot Above]O2max. Exercise time above 80 and 90% of HRmax was longer with 2 and 3 minutes (p ≤ 0.05) as compared with the 4-minute recovery. Oxygen uptake and HR amplitude were lower, mean response time slower (p ≤ 0.05), and blood lactate and RPE higher with 2 minutes compared with 4-minute recovery (p ≤ 0.05). In conclusion, aerobic metabolism attains its upper functional limits with either 2, or 3 or 4 minutes of recovery during the 4 × 4-minute HIIE; thus, all rest durations could be used for the enhancement of aerobic capacity in sports, fitness, and clinical settings. The short (2 minutes) compared with longer (4 minutes) recovery, however, evokes greater cardiovascular and metabolic stress and activates to a greater extent anaerobic glycolysis and hence, could be used by athletes to induce greater overall physiological challenge.

Objective: The aim of this study was to investigate the adaptations of a water-based training program as well as the detraining and retraining effects on physiological parameters in patients with coronary artery disease (CAD). Methods: Twenty-one patients were separated in an exercise group (n = 11) and a control group (n = 10). The exercise group followed three periods: training, detraining and retraining. Each period lasted 4 months. During the training and the retraining periods, the patients performed four sessions of water exercise (not swimming) per week. Results: The water-based program was well-accepted and no adverse effects were observed. The exercise group improved (p < 0.05) their stress-test time (+11.8%), VO_{2 peak} (+8.4%) and total body strength (+12.2%) after the training period; detraining tended to reverse these positive adaptations. Resumption of training increased the beneficial effects obtained after the initial training period (exercise stress: +4.5%; VO_{2 peak}: +6.6%; total strength: +7.0%). The patients in the control group did not show any significant alterations throughout the study. Conclusion: Water-based exercise is safe and induces positive physiological and muscular adaptations in low-risk patients with CAD. These could be reversed, however, after the cessation of exercise. This is why uninterrupted exercise throughout life is a must.

ObjecTIVe: The aim of the present study was to examine the effects of a combined strength and aerobic training program on pro-and anti-inflammatory cytokines and transforming growth factor-β1 in patients with type 2 diabetes. DeSIgn: Ten patients with type 2 diabetes, aged 55.5 (5) years [median (IQR)] participated in a supervised systematic exercise training program which included aerobic exercise and strength training, undertaken four days per week for eight weeks. ReSUlTS: The training program increased transforming growth factor-β1 concentration (+50.4%) and reduced high sensitivity c reactive protein levels (-24.1%) without altering the levels of interleukin-6, interleukin-10, interferon-γ and tumor necrosis factor-α. Additional improvements were also achieved in anthropometric characteristics, glycated hemoglobin (HbA1c: -11.8%), homeostasis model assessment of insulin resistance index (HOMA-IR: -15%) and physical fitness parameters (stress test: +26.6%, upper muscle strength: +32.4% and lower muscle strength: +48.9%). cOnclUSIOn: A combined strength and aerobic exercise program has a potential anti-atherogenic and anti-inflammatory impact which most likely reduces the risk of cardiovascular disease and improves the health status in patients with type 2 diabetes.

This study examined the effects of maximum and submaximum movement velocities after a muscular hypertrophy type resistance exercise protocol on testosterone, human growth hormone (hGH) and cortisol concentrations and on neuromuscular performance assessed with a vertical jump. Eleven males performed a control and 3 resistance exercise protocols (4 sets of squat and 4 sets of leg-press exercises, 8 repetitions/set, 10-repetition maximum load). The first exercise protocol was performed at maximum velocity (Vmax); the second at 70% of Vmax with equal training volume (70%VmaxEV) to Vmax; and the third at 70% of Vmax (70%Vmax) with a 10.6% higher training volume to Vmax. Testosterone and hGH increased after all exercise protocols (p < 0.05) compared with baseline and were higher versus control values (p < 0.05). Cortisol concentrations gradually decreased in 70%Vmax, 70%VmaxEV and control protocols following a typical circadian rhythm (p < 0.05), but remained relatively constant in Vmax protocol. Comparisons among protocols showed that hGH was higher in 70%Vmax versus Vmax (p < 0.05), while cortisol was higher in Vmax versus 70%VmaxEV and control (p < 0.05). The greatest reduction in vertical jump and increase in heart rate were observed after the Vmax protocol (p < 0.05). In conclusion, a hypertrophy type resistance exercise protocol performed at maximum movement velocity increases testosterone and hGH and generates a greater biological stress, as evident by a higher cortisol concentrations and heart rate responses, and a greater reduction in neuromuscular performance. A protocol, however, performed at submaximum movement velocity combined with greater training volume stimulates to a greater extent the hGH response with no effect on cortisol.