The aim of this study was to analyse the acute effects of a concentric exercise and two different eccentric overload exercises (EOEs) on blood markers of muscle damage (i.e. creatine kinase [CK], lactate dehydrogenase [LDH], myoglobin [Myo], and malondialdehyde [MDA]) and muscle contractile properties. Ten healthy, young (27 ± 1.5 years, 179 ± 6 cm, 78.7 ± 10.8 kg), physically active men (3.5 ± 1.9 h·w-1) randomly performed three training sessions using the following protocols: a half-squat (HS) as a concentric exercise, and exercises using Versapulley (VP) or YoYo isoinertial technology (YIT) as EOEs (4 x 7 repetitions with a 2 min rest interval between sets). Blood samples and tensiomyography measurements were obtained after each training session. Repeated measures analysis of variance (ANOVA) followed by the Tukey test was used to detect differences between the four time points of each variable. The standardized difference or effect size (ES, 90% confidence limit) in the selected variables was calculated using the basal SD. After all exercises, a greater activity of CK, LDH, and concentration of Myo, and MDA were found compared to baseline values (p < 0.05). A substantially greater activity of CK, LDH, and Myo concentration, but not MDA, were found after EOEs when compared to the HS protocol. Substantially lower tensiomyography results in the rectus femoris (RF) were reported, irrespective of the exercise mode performed. Also, no substantial differences were obtained in the biceps femoris (BF) between EOEs and the HS protocol. Time of contraction (Tc) in the RF was possibly to very likely lower in the HS in comparison to EOEs. Additionally, muscular displacement (Dm) in the RF was substantially lower in the HS compared to EOEs. VP produced higher concentrations of damage markers than YIT and concentric exercise did. Furthermore, tensiomyography variables showed similar activation in both exercises, although higher specific fatigue (in the RF) was registered in the traditional HS.

 

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Post workout multi-ingredient admixtures are commonly used to maximize recovery after exercise. The present double-blind, cross-over study compared the acute effects of ingesting a protein-vegan multi-ingredient (VGMT) vs. maltodextrin (MALT) on indices of muscle function. Ten trained males, (26.8 ± 1.9 years) performed two identical, 3-day resistance training periods (one workout-session per day) while receiving either VGMT or MALT (10 min after the completion of each workout). Following a baseline evaluation, we conducted assessments at, 1-h, 24-h and 48-h after the 3-day training period. Primary outcome included the evoked tensiomyography contraction velocity (Vc) of vastus medialis (VM), biceps femoris long head (BFLH) and anterior deltoids (AD). Secondary outcomes involved strength and power performance while the other tensiomyography variables [muscle displacement (Dm), contraction time (Tc)] were considered as exploratory. After 1-h, all the tensiomyography variables measured at VM and BFLH were similarly depressed in both treatments. Only MALT showed a significantly lower Vc (−0.02 m. s −1, 95% CI, −0.04, −0.01) in the AD. After 24-h, the VGMT treatment normalized all tensiomyography values. Conversely, impaired scores were observed in Vc for the VM (−0.03 m. s −1, 95% CI, −0.06, −0.01) and BFLH (−0.02 m. s −1, 95% CI, −0.05, 0.01) in the MALT treatment. Particularly, the Vc in VM was lower (p = 0.043) in MALT compared to VGMT. Overall, both treatments required 48-h to regain their performance capacity; however, VGMT produced better vertical jump and squat performance at 24-h vs. MALT. Compared to MALT, a vegan-protein multi-ingredient appears to hasten the recovery of muscular function over a 24-h period.

 

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The purpose was to investigate the effect of rest-redistribution (RR) on muscle damage after eccentric knee extensions. After 2 weeks of eccentric familiarization, 11 resistance-trained men performed 2 work-matched isokinetic unilateral eccentric knee extension protocols at 60°·s−1 using a crossover design, separated by 7 days. Subjects performed 40 repetitions with 285 seconds of rest using traditional sets (TS; 4 sets of 10 with 95 seconds of interset rest) and RR (RR; 20 sets of 2 with 15 seconds of interset rest). Muscle morphology, tensiomyography, range of motion, perceived soreness, and strength were measured before and 0, 24, 48, 72, and 96 hour after RR and TS. There were no protocol × time interactions (p < 0.05). When collapsed across protocol and compared to baseline, echo intensity of the proximal vastus lateralis was 7 ± 9% greater at 0 hour (p = 0.042), echo intensity of the distal vastus lateralis was 6 ± 7% and 9 ± 7% greater at 0 hour (p = 0.048) and 24 hour (p < 0.001), respectively, and passive ROM was 2 ± 1% lower at 48 hour (p = 0.043) after exercise. No other differences existed over time for any other variable. Thus, contrary to concentric performance where RR likely plays a large role in maintaining performance, RR during eccentric isokinetic resistance training does not strongly influence exercise performance and indications of subsequent muscle damage.

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Is tensiomyography sensitive enough?

New technological advances are constantly being developed to assess fatigue and muscle damage in sports. Tensiomyography (TMG) has been used as an alternative method to indirectly assess these physiological responses. The aim of this study was to explore the potential use of TMG parameters (muscle radial deformation [Dm], time of contraction [Tc], delay time [Td], deformation rate until 10% [V10] and 90% [V90]) to detect neuromuscular acute fatigue-related responses during a duathlon compared to well-known biochemical (blood lactate [BLa]), perceptual (rate of perceived exertion [RPE]), and functional (jump performance [CMJ]) variables. Twenty-three well-trained athletes (age 33.6 ± 7.2 years, weight 64.4± 9.2 kg, height 1.7 ± 0.2 m, VO2max 56.7± 6.9 mL/kg/min, body fat 16.6 ± 8.4%, lean mass 53.2 ± 11.6 kg) performed a 5k-25k-5k duathlon under controlled indoor conditions at 23°C. TMG muscle properties (left and right gastrocnemius lateralis), BLa, RPE, and CMJ were measured pre-duathlon, during transition 1 (T1), during transition 2 (T2), and post-duathlon. After one-way analyses of variance, there were large differences in BLa (p< 0.01), RPE (p< 0.01) and CMJ (p< 0.01). Large differences (p< 0.01) were also found in Tc, Dm, Td, V10, and V90 as TMG muscle mechanical markers. Compared to well-known fatigue variables (CMJ, RPE, and BLa), Tc and Dm as TMG parameters measured in gastrocnemius lateralis seem to be sensitive enough to detect acute fatigue-related changes during duathlon. Differences reported in Td, V10, and V90 could be the result of muscle post-activation potentiation (PAP) after T1, and more evidence is needed for understanding this PAP phenomenon using TMG.

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The aim of this study was to investigate the neuromuscular response of knee flexor and extensor muscles using the tensiomyography (TMG) method and to compare the TMG characteristics between the dominant and non-dominant lower extremity in male karate competitors. Muscle mechanical properties were recorded from the rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF) and semitendinosus (ST) muscles of both legs. Three TMG parameters were analysed: maximal displacement (Dm), contraction time (Tc), and delay time (Td). Dm and Td parameters of the measured muscles were not affected by the lower extremity dominance in karate athletes. The dominant leg demonstrated a higher Tc of the RF (p = 0.013) and lower Tc of the BF (p = 0.004) compared to the non-dominant leg. A higher Tc of the RF occurs because of the controlled nature of punches and kicks. A lower Tc of the BF is due to the specific requirements of the fighting stance and frequent external hip rotation in karate techniques.

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Tensiomyography (TMG) is an injury detecting tool for muscle group imbalances and/or side-to-side asymmetries. It is liable to detect to measure contractile properties and mechanical responses based on muscle belly displacement. Although other previous papers have well suggested the methods for examining the several muscle groups using TMG, a detecting method for the imbalances in low back muscles has not been investigated, and no review papers have been compiled. Therefore, this study aimed to synthesize the theories of the previous studies observed using TMG and to briefly summarize its usefulness by performing simple experiments on the left and right regions of the erector spinae muscles, which may be a problem using TMG for patients with low back pain.

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This study aimed to evaluate the degree to which transcutaneous electrical stimulation (ES) enhanced recovery following a simulated water rescue. Twenty-six lifeguards participated in this study. The rescue consisted of swimming 100 m with fins and rescue-tube: 50 m swim approach and 50 m tow-in a simulated victim. Blood lactate clearance, rated perceived effort (RPE), and muscle contractile properties were evaluated at baseline, after the water rescue, and after ES or passive-recovery control condition (PR) protocol. Tensiomiography, RPE, and blood lactate basal levels indicated equivalence between both groups. There was no change in tensiomiography from pre to post-recovery and no difference between recovery protocols. Overall-RPE, legs-RPE and arms-RPE after ES (mean ± SD; 2.7 ± 1.53, 2.65 ± 1.66, and 2.30 ± 1.84, respectively) were moderately lower than after PR (3.57 ± 2.4, 3.71 ± 2.43, and 3.29 ± 1.79, respectively) (p = 0.016, p = 0.010, p = 0.028, respectively). There was a significantly lower blood lactate level after recovery in ES than in PR (mean ± SD; 4.77 ± 1.86 mmol·L-1 vs. 6.27 ± 3.69 mmol·L-1; p = 0.045). Low-frequency ES immediately after a water rescue is an effective recovery strategy to clear out blood lactate concentration.

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This study aimed to analyse the effect of playing surface temperature on muscular and thermal response to a repeated-sprint ability (RSA) test in football players. Thirty-two male football players (23 ± 5 years; 1.77 ± 0.06 m; 71.2 ± 6.7 kg) from two squads of a third-division football club participated in the study. An RSA test was carried out at a high surface temperature (45.34 ± 2.53 °C) and low surface temperature (27.21 ± 2.17 °C). Before and after this test, the muscular response of the players was assessed through tensiomyography and thermograms. The results revealed that performance in the RSA test particularly increased at a higher surface temperature, especially in the first 5 m of the 30 m sprint test. While a reduction in maximal radial displacement (Dm) in the biceps femoris post-RSA was observed at lower surface temperatures, a higher temperature on the thigh, hamstring and calf was found in the higher surface temperature group. In conclusion, higher surface temperatures had an influence on players’ thermal and tensiomyographic profile and improved performance in their repeated-sprint ability. These results suggest a need for coaches and players to be aware of these parameters to ensure adequate functionality and safety of the playing surface.

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Background and objectives: Patient-handling activities predispose women to chronic low back pain (CLBP), but sufficient evidence is not available on whether a 3D moving platform, made for core stability exercise, affects pain, trunk flexibility, and static/dynamic muscle contractions in CLBP patients. Materials and Methods: The participants were twenty-nine women who were randomly divided into a control group (CON) and a 3D exercise group (3DEG), which took part in 3D moving exercise three times a week for 8 weeks. Both groups measured a visual analog scale (VAS) about their CLBP. Body composition, forward and backward trunk flexibilities, static muscle contraction property in rectus abdominis, and erector spinae were measured by tensiomyography, which found contraction time (Tc) and maximal displacement (Dm). Dynamic muscle contraction property in the abdomen and back were measured with an isokinetic device, which could measure peak torque (Pt) and work per repetition (Wr), before and after the trial.

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