Can different variations of suspension exercises provide adequate loads and muscle activations for upper body training?

The purpose of this study was to assess the differences in muscle activation (EMG) and body weight distribution (%BW) between suspension (TRX™ push-up and TRX™ inverted row) and conventional exercises (bench press and lying barbell row) using different contraction types (isometric and isotonic) and position variations (feet on the ground [FG] and feet on suspension device [FD]). It was also used to determine the intensity of the force applied to the straps of the suspension device corresponding to one repetition maximum (1-RM). Twelve male athletes (ages-24.5±4.2 years (mean±standard deviation [SD]); Height-181.0±6.8 cm; body mass-83.08±6.81 kg) participated in this study. Two suspension devices were used, one for the FD variation and one for the FG variation pectoralis major (PM) and triceps brachii (TRI) activations were assessed during the TRX™ push-up and bench press exercises. Transversus trapezius (TRA) and biceps brachii (BB) activations were assessed during the TRX™ inverted row and lying barbell row exercises. The results showed significant differences between exercises (FG and FD variations of TRX™ push-up and bench press) in PM activities (isometric and isotonic) (p≤0.05). However, these differences were only observed during isometric TRI activation (p≤0.05). In the FG and FD variations of the TRX™ inverted row and lying barbell row exercises, there were only differences in the isometric contractions of the TRA and BB (p≤0.05). In the suspension device of push-ups and inverted row for the FD variations, 70.5% and 72.64% of 1-RM intensity were obtained, respectively. Similar responses to training intensities and muscle activations can be obtained in suspension exercises and conventional exercises. FD variations of suspension exercises can be more effective in terms of muscle activations than FG variations, and isotonic suspension exercises increase exercise intensity more than isometric suspension exercises.

The effect of mouth rinsing with different concentrations of caffeine solutions on reaction time.

Caffeine mouth rinsing (CAF-MR) has been shown to improve reaction time (RT). CAF-MR studies have generally used 1.2% CAF concentrations, but the effect of using different concentrations is unknown. Therefore, we compared the effect of different concentrations of CAF-MR on RT. Forty-five trained male athletes (age: 18 ± 3 y) volunteered to participate in this double-blind, randomized controlled crossover study. Participants completed five testing sessions (Control, Placebo (water)-MR, and 1.2%, 1.8%, and 2.4% CAF-MR), with hand and foot RTs assessed immediately after MR. All CAF-MR conditions resulted in significantly faster hand and foot RT compared to Control and Placebo (all p < 0.001, except for foot RT with 1.8% CAF-MR vs. Placebo: NS). For both hand and foot RT, 1.2% and 1.8% CAF-MR did not significantly differ, but RT for 2.4% CAF-MR was significantly faster than both (p < 0.001). Improvements in RT for 2.4% CAF-MR vs. Placebo were 22% for hand RT and 21% for foot RT. In conclusion, these findings demonstrate that higher CAF-MR concentrations than those typically used can result in greater improvements in RT. This has implications for the practical use of CAF-MR to enhance performance in sports in which optimal RT is a factor of success.

Assessments of Ground Reaction Force and Range of Motion in Terms of Fatigue during the Body Weight Squat.

The purpose of this study was to analyse in detail body weight squat (BWS)' fatigue effect on the range of motions (ROM) of the hip, knee, ankle and ground reaction forces (GRF). Twenty male recreational athletes (24.0 ± 3.1 years, 178.85 ± 7.12 cm and 78.7 ± 11.45 kg) participated in this study. BWS were performed on four load cell platforms until the participants failed to continue. Participants performed 73 ± 27 repetitions and the duration to complete of the repetitions was 140.72 ± 62.28 s during the BWS exercise. The forefoot and hindfoot of the feet were on two load cells, thus, there were two under each foot. All of the data collected was divided into three sections for analysis (24 ± 9 repetitions for each). In terms of GRF of the fore feet and hind feet, significant differences and medium to large effect size were found between each section (p = 0.006~0.040, ES = 0.693~0.492). No significant differences were found between right and left leg in all sections. Significant differences were found in the ROM of the hip between the sections of first-third (p = 0.044, ES = 0.482) and second-third (p = 0.034, ES = 0.510), the ROM of the knee first-third (p = 0.014, ES = 0.602) and second-third (p = 0.005, ES = 0.701) and for the ROM of the ankle first-second (p = 0.045, ES = 0.479). As a result, end-of-exercise fatigue caused an increase in the ROM of the hip, knee and ankle. Thus, it is observed that fatigue induced increased ROM, also increases the GRF towards the forefeet.

Decreasing sprint duration from 20 to 10 s during reduced-exertion high-intensity interval training (REHIT) attenuates the increase in maximal aerobic capacity but has no effect on affective and perceptual responses.

Recent studies have demonstrated that modifying the "classic" 6 × 30-s "all-out" sprint interval training protocol by incorporating either shorter sprints (6 × 10-s or 15-s sprints) or fewer sprints (e.g., 2 × 20-s sprints; reduced-exertion high-intensity interval training (REHIT)) does not attenuate the training-induced improvements in maximal aerobic capacity. The aim of the present study was to determine if reducing the sprint duration in the REHIT protocol from 20 s to 10 s per sprint influences acute affective responses and the change in maximal aerobic capacity following training. Thirty-six sedentary or recreationally active participants (17 women; mean ± SD; age: 22 ± 3 years; body mass index: 24.5 ± 4.6 kg·m-2; maximal aerobic capacity: 37 ± 8 mL·kg-1·min-1) were randomised to a group performing a "standard" REHIT protocol involving 2 × 20-s sprints or a group who performed 2 × 10-s sprints. Maximal aerobic capacity was determined before and after 6 weeks of 3 weekly training sessions. Acute affective responses and perceived exertion were assessed during training. Greater increases in maximal aerobic capacity were observed for the group performing 20-s sprints (2.77 ± 0.75 to 3.04 ± 0.75 L·min-1; +10%) compared with the group performing 10-s sprints (2.58 ± 0.57 vs. 2.67 ± 3.04 L·min-1; +4%; group × time interaction effect: p < 0.05; d = 1.06). Positive affect and the mood state vigour increased postexercise, while tension, depression, and total mood disturbance decreased, and negative affect remained unchanged. Affective responses and perceived exertion were not altered by training and were not different between groups. In conclusion, reducing sprint duration in the REHIT protocol from 20 s to 10 s attenuates improvements in maximal aerobic capacity, and does not result in more positive affective responses or lower perceived exertion.