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Ultra-short race-pace training (USRPT) is a high-intensity training modality used in swimming for the development of specific race-technique. However, there is little information about the fatigue associated to this modality. In a crossover design, acute responses of two volume-equated sessions (1000-m) were compared on 14 national swimmers: i) USRPT: 20×50-m; ii) RPT: 10×100-m. Both protocols followed an equivalent work-recovery ratio (1:1) based on individual 200-m race-pace. The swimming times and the arm-strokes count were monitored on each set and compared by mixed-models. Blood lactate [La-] and countermovement jump-height (CMJ) were compared within and between conditions 2 and 5 min after the protocols. The last bouts in RPT were 1.5–3% slower than the target pace, entailing an arm-strokes increase of ~0.22 for every second increase in swimming time. USRPT produced lower [La-] ([Mean ± standard deviation], 2 min: 8.2±2.4 [p = 0.021]; 5 min: 6.9±2.8 mM/L [p = 0.008]), than RPT (2 min: 10.9±2.3; 5 min: 9.9±2.4 mM/L). CMJ was lowered at min 2 after RPT (-11.09%) and USRPT (-5.89%), but returned to baseline in USRPT at min 5 of recovery (4.07%). In conclusion, lower fatigue and better recovery were achieved during USRPT compared to traditional high-volume set. [ABSTRACT FROM AUTHOR]

It has been purported that the mechanism for muscular improvement after a gluteal warm-up protocol is likely to occur from neural activation. However, little is known about whether changes in muscular performance are due to changes in muscle activity. Therefore, the aim of this study was to determine whether a lower-limb warm-up that targets the gluteal muscle group would improve countermovement jump and short-distance sprinting through increased muscle activity. Ten semi-professional rugby union players (age 25.4 ± 2.9 yr; height 1.83 ± 6.7 m; body mass 96.8 ± 10.6 kg) with at least three years of resistance training experience volunteered for the study. In a cross-over design, participants performed countermovement jumps and 5 m sprints before and after a gluteal warm-up and a 10 min rest (control). Electromyography was used to measure muscle activity of the gluteus maximus and biceps femoris. Countermovement jump height significantly improved (7.9%, p < 0.05) after the lower-limb warm-up protocol compared with the control (3.2%). There was a significant (p < 0.05) improvement in sprint times over 2.5 m and 5 m regardless of the condition. There was no significant change in the muscle activity in any of the conditions. The results indicate that a lower-limb warm-up can acutely enhance countermovement jump performance compared to a control. [ABSTRACT FROM AUTHOR]

The purpose was to determine the effect of lowering minimum eye height through an externally focused object on knee and hip flexion and impact forces during jump-landing. Kinematics and ground reaction forces were collected when 20 male and 19 female participants performed jump-landing trials with their natural minimum eye height, and trials focusing on lowering their minimum eye height to an external object, which was set at 5% or 10% of standing height lower. Participants demonstrated decreased minimum eye height and increased peak knee and hip flexion during early-landing and stance phase when focusing on lowering eye height to the external object (p < 0.01). Peak vertical ground reaction forces during early-landing also decreased for the greater force group (p < 0.001). Jump-landing training through manipulating eye height provides a strategy that involves an external focus and intrinsic feedback, which may have advantages in promoting learning and practical application. [ABSTRACT FROM AUTHOR]

The study aimed to determine whether or not commercial golf gloves influence performance variables and forearm muscle activity during golf play. Fifteen golfers participated in the laboratory based study, each performing 8 golf swings with a Driver and 7-iron whilst wearing a glove and 8 without wearing the glove. Club head speed, ball speed and absolute carry distance performance variables were calculated. Surface electromyography was recorded from the flexor digitorum superficialis and extensor carpi radialis brevis on both forearm muscles. Club head speed, ball speed and absolute carry distance was significantly higher when using the Driver with the glove in comparison to the Driver without the glove (p < 0.05). No significant differences were evident when using the 7-iron and no significant differences were displayed in muscle activity in either of the conditions. Findings from this study suggest that driving performance is improved when wearing a glove. [ABSTRACT FROM AUTHOR]

A reduction in gluteus maximus (GM) strength may contribute to the etiology of musculoskeletal impairments and lower-extremity injuries. Currently, there is a paucity of evidence regarding the efficacy of implementing a short-term gluteal activation programme to improving muscle performance. Twenty four semi-professional rugby males were assigned randomly to a gluteal activation group (GLUTE) or a control group (CON). During the 6-week training intervention, the GLUTE and CON groups performed the same training, however that GLUTE group performed seven gluteal activation exercises three times weekly prior to their normal training sessions. Whilst the CON group performed the conventional training with no gluteal activation exercises. Electromyography (EMG) was measured during a maximal isometric unilateral squat (MVIC) and unilateral hip extension force from the left and right vastus lateralis, gluteus maximus, and biceps femoris. After 6 weeks of training there was no significant main or interaction effect (p > 0.05) of EMG and peak force for MVIC and hip extension between GLUTE and CON. The current gluteal activation programme did not enhance EMG activity and hip extension force therefore, the body-weight exercises may not have been sufficient to elicit the appropriate changes. [ABSTRACT FROM AUTHOR]

This study examined the effects of regular Tai Chi practice and jogging on the neuromuscular activity of the trunk, hip, and ankle joint muscles of older people during lateral postural perturbation. A total of 42 older people participated in the study and formed the Tai Chi, jogging, and sedentary control groups. Electromyography signals were collected from the peroneus longus, anterior tibialis, gluteus medius, and erector spinae during unpredictable mediolateral perturbation. The Tai Chi group exhibited significantly faster latencies of the tibialis anterior and erector spinae than the control group. The jogging group showed a significantly shorter neuromuscular reaction time of the erector spinae than the control group. No significant difference was observed between the Tai Chi and jogging groups. Long-term regular Tai Chi practice enhanced the neuromuscular reaction of the erector spinae and tibialis anterior to lateral perturbation and will help timely posture correction when lateral postural distributions occur. [ABSTRACT FROM PUBLISHER]

This study assessed the effect of 1-year regular Tai Chi (TC) on neuromuscular reaction in elderly women. A total of 41 elderly women (55 years–68 years) completed the study. The TC group (n = 21) performed the 24-form TC, while the control group (C, n = 20) was instructed to read newspapers or watch television when the TC group practised. Electromyogram measurements were conducted before and after intervention. After a year-long intervention, the post-test results of between-group neuromuscular reaction time showed significant differences in the rectus femoris (t = 3.607, p = 0.001), semitendinosus (t = 2.678, p = 0.011), anterior tibialis (t = 3.455, p = 0.001), and gastrocnemius muscles (t = 4.061, p = 0.000). Within-group results showed that the TC group had significantly shorter neuromuscular reaction time compared to its baseline value in the rectus femoris (t = 3.066, p = 0.006), semitendinosus (t = 2.485, p = 0.022), anterior tibialis (t = 2.311, p = 0.032), and gastrocnemius muscles (t = 2.462, p = 0.023). Results suggested that year-long regular TC can improve neuromuscular reaction function in elderly women. [ABSTRACT FROM AUTHOR]

Landing and squat tasks have been utilized to assess lower extremity biomechanics associated with anterior cruciate ligament loading and injury risks. The purpose of this study was to identify the differences and correlations in knee and hip mechanics during a single-leg landing, a single-leg squat, a double-leg landing, and a double-leg squat. Seventeen male and 17 female recreational athletes performed landings and squats when kinematic and kinetic data were collected. ANOVAs showed significant differences (p < 0.00001) for maximum knee flexion angles, maximum hip flexion angles, maximum knee abduction angles, maximum hip adduction angles, and maximum external knee abduction moments among squats and landings. For maximum knee and hip flexion angles, significant correlations (r ≥ 0.5, p ≤ 0.003) were observed between the two landings and between the two squats. For maximum knee abduction and hip adduction angles and maximum external knee abduction moments, significant correlations were mostly found between the two landings, and between the single-leg squat and landings (r ≥ 0.54, p ≤ 0.001). Individuals are likely to demonstrate different profiles of injury risks when screened using different tasks. While a double-leg landing should be considered as a priority in screening, a single-leg squat may be used as a surrogate to assess frontal plane motion and loading. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the muscle activity and onset time of hip extensors during a closed kinetic chain exercise (deadlift) at sub-maximal loads of 30%, 40%, 50%, and 75% of one repetition maximum (1RM). Twelve healthy males with at least three years of resistance training experience volunteered for the study. Biceps femoris (BF) and gluteus maximus (GM) muscle activity, onset time, peak and mean power were measured during the concentric phase of the deadlift. There was no main effect (p > 0.05) or no interaction effect for the onset time in BF and GM and for each load BF and GM had similar muscle activity. Increasing the external load during deadlift had no adverse effect on the relative onset time and it did not promote BF onset to occur before GM onset, thus both muscles were simultaneously activated, which should not compromise a delay in GM. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the spinal posture in young athletes depending on training intensity. The spinal curvature of 245 children, age 8 to 12 years, was evaluated using rasterstereography. According to their weekly training time group 1 (mean age: 9.54 ± 1.18) did 2–6, group 2 (mean age: 9.49 ± 0.87) did 6–15 and group 3 (mean age: 9.68 ± 0.87) did over 15 hours of training. Group 1 had a significantly higher weight (p= 0.028) (33.86 ± 7. kg) than those of the more active groups (30.67 ± 6.49 kg and 29.46 ± 4.33 kg). The mean kyphotic angle decreased significantly (p< 0.001) with the amount of training per week from 46.86 ± 8.2° in group 1 to 40.08 ± 8° in group 3. We also found a significant decrease (p= 0.047) in lateral deviation with training from group 1 with 5.3 ± 3 mm to group 2 with 4.1 ± 1.6 mm. The results of our study suggest that higher training time can be associated with lower weight and decreases in thoracic kyphosis and lateral deviation of the spine. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effects of antagonist passive static stretching (AS) during the inter-set rest period on repetition performance and muscle activation. Ten trained men (22.4 ± 0.9 years) participated in this study. Two protocols were adopted: Passive recovery (PR) – three sets to repetition failure were performed for the seated row (SR) with two-minute rest interval between sets without pre-exercise stretching; AS – forty seconds of stretching was applied to pectoralis major prior to each set of SR. Significant increases in the number of repetitions were noted under AS compared with PR (p < 0.05). Significant increases on latissimus dorsi (p = 0.002) and biceps brachii (p = 0.001) muscle activity were noted inter-sets under the AS compared with the PR condition. Therefore, the AS adopted during the inter-set rest period may enhance repetition performance and activation of agonist muscles in an acute manner. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate upper body muscle activity during a 30 s Wingate test. Eighteen physically active participants performed a Wingate test while muscle activity was recorded from the brachioradialis (BR), biceps brachii (BB), triceps brachii (TB) and upper trapezius (UT). Measurements were obtained at rest, during a function maximal contraction (FMC) and during the 30 s Wingate test, whilst participants were positioned in a seated position on the cycle ergometer. All muscles were significantly active for the duration of the test. When normalized as a %FMC no differences in activity were found between muscles. Across the 30 s, power output was found to significantly decrease, whereas no changes were found in upper body muscle activity. All muscles investigated were active during the Wingate test and therefore confirmed previous findings that the upper body significantly contributes to power profiles obtained during high intensity cycle ergometry in addition to its role in stabilizing the body. [ABSTRACT FROM AUTHOR]

This study explored the trunk and lower limb muscle activity of 15 males during unilateral hockey bag carriage of 10%, 20%, and 30% of one’s body weight (BW) compared with without a load during walking. The electromyography (EMG) activities of the left and right erector spinae, rectus abdominis, gluteus maximus, rectus femoris, vastus medialis, biceps femoris, semitendinosus, and the medial gastrocnemius were studied. A 2-way repeated measures analysis of variance (ANOVA) was used to examine the differences between the load weight and muscle side. Results showed significant increase in peak EMG and iEMG in the carrying side vastus medialis, rectus abdominis, semitendinosus, and gastrocnemii (p < 0.05) at the 30% BW load. The noncarrying side showed a greater peak EMG in the semitendinosus and rectus femoris at the 30% BW load when compared with the carrying side (p < 0.05). It was concluded that unilateral hockey bag carriage is similar to both backpack and side-pack carriage styles. [ABSTRACT FROM PUBLISHER]

Little information exists on how body weight (BW) support influences running biomechanics. The study aim was to determine how reducing BW by 50%–80% influences muscle activity while running at different speeds. Subjects (n = 7) ran at 100%, 115%, 125% of preferred speed at 100%, 50%, 40%, 30%, 20% of BW per speed. Average (AVG) electromyography of the rectified signal was compared (within subject design; 3-speeds × 5-BW, repeated measures ANOVAs; biceps femoris [BF], rectus femoris [RF], tibialis anterior [TA], gastrocnemius [GA]). RF, BF, and GA AVG were not influenced by BW–speed interaction (p> .05) and increased across speeds (p< .05). RF and GA AVG signal was reduced as BW was reduced (p< .05), but BF only tended to be different (p= .08). TA was influenced by BW–speed interaction (p< .05) with EMG decreasing across BW (p< .05) while increasing across speeds except at 100% BW. Overall, muscle activity increased with speed and decreased by BW reductions. [ABSTRACT FROM PUBLISHER]