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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The aim of this research is to assess the muscle balance of thigh muscle in MS using a noninvasive method, to have information about the muscle status prior to the rehabilitation and to prevent muscle damage.
Chronic demyelinisation in multiple sclerosis (MS) involves changes in the muscle structure and development of motor disorders.
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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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They studied the effects of age on different physiological parameters, including those derived from the i) maximal cardiopulmonary exercise testing (CPET), ii) moderate-intensity step-transitions and iii) tensiomyography (TMG)-derived variables in moderately active women. Twenty-eight women (age range from 19 to 53 y), completed three laboratory visits, including baseline data collection, TMG assessment, V̇O2 max. test via CPET, and a step-transition test from 20 W to a moderate-intensity cycling power output (PO), corresponding to V̇O2 at 90% gas exchange threshold. During the step-transitions breath-by-breath pulmonary oxygen uptake (V̇O2p), near infrared spectroscopy derived muscle deoxygenation (ΔHHb), and beat-by-beat cardiovascular response were continuously monitored. There were no differences observed between the young and middle-aged women in their V̇O2 max. and peak PO, while the HR max. was 12 bpm lower in middle-aged compared to young (p=.016). Also, no differences were observed between the age groups in τV̇O2p, ΔHHb, and τHR during on-transients. The first regression model showed that age did not attenuate the maximal CPET capacity in the studied population (p=.638), while in the second model a faster τV̇O2p, combined with shorter TMG-derived contraction time (Tc) of the vastus lateralis (VL), were associated with a higher V̇O2 max. (~30% of explained variance, p=.039). In conclusion, long lasting exercise involvement protects against a V̇O2 max. and τV̇O2p deterioration in moderately active women. Novelty bullets: • Faster pulmonary τV̇O2p and shorter Tc of the VL explain 33% of the variance in superior V̇O2 max. attainment; • No differences between age groups were found in τV̇O2p, τΔHHb, τHR, during on-transient.
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Congested-fixture championships are common during the selection of the athletes and teams participating in the Olympic Games. Throughout these tournaments, it is fundamental to perform optimally, rest well, and recover between competitions. This study aimed to a) explore the effectiveness of the use of intermittent pneumatic compression (IPC) and cold water immersion (CWI) to recover muscle mechanical function (MuscleMechFx), hydration status (HydS), pain perception (PainPercep), rate of perceived exertion (RPE), sleep hours, and sleep quality (SleepQual) during a regional multi-sports international championship and b) compare these results by sex. Methods: A total of 52 basketball and handball players were exposed to a recovery protocol after the competition as follows: IPC, sequential 20 min at 200 mmHg, and CWI, continuous 12 min at 12 °C. Results: MuscleMechFx presented differences by match and sex (p = 0.058) in time of contraction of biceps femoris; SleepQual and sleep hours were different between matches (<0.01). Conclusions: IPC + CWI seems to be effective to maintain some MuscleMechFx, HydS, and recovery and pain perception during a congested multi-sport tournament.
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The aim of this study was to investigate the differences in mechanical and contractile properties of knee joint flexor and extensor muscles between differently trained men and women, using tensiomyography (TMG). The sample consisted of 159 subjects (84 men and 75 women), who were assigned to one of 5 groups according to the following levels and types of their physical activity: physically inactive, physically active nonathletes, strength and power athletes, endurance athletes, and team sports athletes. Measurements were performed on the following knee flexor and extensor muscles of the dominant leg: rectus femoris, vastus medialis, vastus lateralis, biceps femoris, and semitendinosus. The results showed significant differences in contraction time—Tc and delay time—Td parameters between differently trained men and women, whereas in other TMG parameters, there were no differences between groups. It is indicated that physical activities characteristic of strength and power sports (combat sports and sprint disciplines) could lead to an increased speed of twitch force generation and fast twitch muscle fibers, and that almost any regular, systematic, and planned physical activity leads to increased muscle responsiveness. Obtained results also indicated that TMG parameters do not have enough specific discriminatory power for detecting differences between differently trained young adults.
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