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Neuromuscular warm-up positively affects motor abilities and muscle performance. The purpose of the study was to extend the knowledge about the effect of neuromuscular warm-up on the level of muscle contractility in female football players. The research sample consisted of experimental (EG, n=20) and control (CG, n=16) groups of female football players. The intervention lasted 12 weeks. The neuromuscular warm-up was implemented in the experimental group, while the control group performed a standard warm-up. Muscle contractility was assessed in dominant (DLE) and non-dominant (NDL) legs using Tensiomyograph (TMG-S2) (TMGBMC Ltd., Ljubljana, Slovenia, 2011) with emphasis on m.biceps femoris, m.gastrocnemius medialis, m.gluteus maximus, m.vastus lateralis, and m.vastus medialis. Muscle contractility was assessed with an emphasis on contraction velocity (Vc). Wilcoxon test was used to determine significant differences. After the intervention, there was a significant improvement in the contraction velocity of m. vastus lateralis DLE (p=0.040, r=0.342) and m. vastus medialis NDL (p=0.048, r=0.330). In contrast to these findings, when the standard warm-up was applied, a significant improvement was observed in the contraction velocity of m. vastus medialis NDL (p=0.011, r=0.422). Additionally, there was a decrease in the contraction velocity of m. biceps femoris, m. gastrocnemius medialis, and m. vastus lateralis in both dominant and non-dominant legs, though the decrease was not significant. Based on the results, it is concluded that NMT warm-up significantly improved the contraction velocity in specific muscles (m. vastus lateralis DLE and m. vastus medialis NDL) in the experimental group. However, the effects on other muscles were not as pronounced, and the standard warm-up showed different results. Therefore, NMT warm-up has an impact on muscle contraction velocity, but the extent and consistency of this effect vary. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess whether tensiomyography is a tool sensitive enough to detect peripheral fatigue. Twenty-six strength-trained men were split into two groups: 1) a fatigued group (FG), who performed a fullsquat (SQ) standardized warm-up plus 3 x 8 SQs with 75% 1RM with a 5-min rest interval, and 2) a non-fatigued group (NFG), who only did the SQ standardized warm-up. The countermovement jump (CMJ), maximal isometric force (MIF) in the SQ at 90° knee flexion, and TMG in vastus medialis (VM) and vastus lateralis (VL) muscles were assessed preand post-protocols. Data were analyzed through mixed ANOVA, logistic regression analysis, and receiver-operating curves. There were significant group x time interactions (p < 0.01) for CMJ height, MIF, maximal radial displacement (Dm), and radial displacement velocity (Vrd90) since the FG acutely decreased in these variables, while no significant changes were observed for the NFG. The logistic regression showed a significant model for detecting fatigue, whether it used the CMJ or MIF, with only the relative change in VL-Vrd90 as a fatigue predictor. The determination of the area under the curve showed that Dm and Vrd90 had good to excellent discriminative ability. Dm and Vrd90 are sensitive to detect fatigue in VL and VM muscles in resistance training contexts. [ABSTRACT FROM AUTHOR]

Context: Exercise-induced muscle damage (EIMD) is prevalent especially in sports and rehabilitation. It causes loss in skeletal muscle function and soreness. As there are no firm preventive strategies, we aimed to evaluate the preventive efficacy of nonthermal 448-kHz capacitive resistive monopolar radiofrequency (CRMRF) therapy after eccentric bouts of EIMD response in knee flexors. Design: Twenty-nine healthy males (age: 25.2 [4.6] y) were randomized in control group (CG; n = 15) and experimental group (EG; n = 14) where EG followed 5 daily 448-kHz CRMRF therapies. All assessments were performed at baseline and post EIMD (EIMD + 1, EIMD + 2, EIMD + 5, and EIMD + 9 d). We measured tensiomyography of biceps femoris and semitendinosus to calculate contraction time, the maximal displacement and the radial velocity of contraction, unilateral isometric knee flexors maximal voluntary contraction torque, and rate of torque development in first 100 milliseconds. Results: Maximal voluntary contraction torque and rate of torque development in first 100 milliseconds decreased more in CG than in EG and recovered only in EG. Biceps femoris contraction time increased only in CG (without recovery), whereas in semitendinosus contraction time increased in EG (only at EIMD + 1) and in CG (without recovery). In both muscles, tensiomyographic maximal displacement decreased in EG (in EIMD + 1 and EIMD + 2) and in CG (without recovery). Furthermore, in both muscles, radial velocity of contraction decreased in EG (from EIMD + 1 until EIMD + 5) and in CG (without recovery). Conclusion: The study shows beneficial effect of CRMRF therapy after inducing EIMD in skeletal muscle strength and contractile parameters in knee flexors. [ABSTRACT FROM AUTHOR]

To compare the acute responses to different set configurations (cluster [CLU] vs. traditional [TRA]) under distinct blood flow conditions (free vs. restricted) in full-squat (SQ). Twenty resistance-trained males performed 4 protocols that differed in the set configuration (TRA: continuous repetitions; vs. CLU: 30 seconds of rest every 2 repetitions) and in the blood flow condition (FF: free-flow; vs. blood flow restriction [BFR]: 50% of arterial occlusion pressure). The relative intensity (60% 1RM), volume (3 sets of 8 repetitions), and resting time (2 minutes) were equated. Mean propulsive force (MPF), velocity (MPV) and power (MPP), and electromyography (EMG) parameters were recorded during each repetition. Ten-siomyography (TMG), blood lactate, countermovement jump (CMJ) height, maximal voluntary isometric contraction, in SQ, and movement velocity against the load that elicited a 1 m⋅s-1 velocity at baseline (V1-load) in SQ were assessed at pre- and post-exercise. The CLU protocols allowed a better maintenance of MPF, MPV, MPP, and EMG median frequency during the exercise compared to TRA (clu-time interaction, p < 0.05). The TRA protocols experienced greater impairments post-exercise in TMG- and EMG-derived variables (clu-time interaction, p < 0.05) and SQ and CMJ performance (clu-time interaction, p = 0.08 andp < 0.05, respectively), as well as higher blood lactate concentrations (clu-time interaction, p < 0.001) than CLU. Moreover, BFR displayed decreases in TMG variables (bfr-time interaction, p < 0.01), but BFR-CLU resulted in the greatest reduction in twitch contraction time (p < 0.001). Cluster sets reduced fatigue during and after the training session and BFR exacerbated impairments in muscle mechanical properties; however, the combination of both could improve contraction speed after exercise. [ABSTRACT FROM AUTHOR]

Trunk muscles' function and characteristics are of great importance for both static and dynamic tasks in different sports, and abnormalities of trunk flexors and extensors might be associated with low back pain (LBP). The aim of this study was to provide a comprehensive evaluation of the functional, morphological and contractile properties in trunk flexors and extensors of young gymnasts with and without LBP. Young gymnasts (14/25 females, 14–18 y) were screened for the presence of chronic LBP. Abdominal and lumbar muscles were tested for function (McGill's endurance tests), thickness (ultrasound), and contractile responses (tensiomyography). An 8-sessions physiotherapy intervention including postural reeducation was performed by a subsample of 10 subjects with LBP. LBP was found to be associated to higher flexors-to-extensors endurance ratio (OR 11.250, 95% CI: 1.647–76.849, p = 0.014), reduced mean lumbar multifidus thickness (OR 16.500, 95% CI: 2.246–121.228, p = 0.006), and reduced mean erector spinae radial displacement (OR 16.500, 95% CI: 2.246–121.228, p = 0.006). The physiotherapy intervention was found to reduce LBP symptoms and it was associated with a significant improvement in the flexors-to-extensors ratio (p < 0.001). This study provides preliminary evidence of functional, morphological, and contractile trunk muscles' alterations associated with chronic LBP in young gymnasts, and presents the effects of a postural reeducation program on symptoms and muscles' functional properties. [ABSTRACT FROM AUTHOR]

(1) Background: The aim of this paper is to analyze the acute effects of different velocity loss (VL) thresholds during a full squat (SQ) with blood-flow restriction (BFR) on strength performance, neuromuscular activity, metabolic response, and muscle contractile properties. (2) Methods: Twenty strength-trained men performed four protocols that differed in the VL achieved within the set (BFR0: 0% VL; BFR10: 10% VL; BFR20: 20% VL; and BFR40: 40% VL). The relative intensity (60% 1RM), recovery between sets (2 min), number of sets (3), and level of BFR (50% of arterial occlusion pressure) were matched between protocols. Tensiomyography (TMG), blood lactate, countermovement jump (CMJ), maximal voluntary isometric SQ contraction (MVIC), and performance with the absolute load required to achieve 1 m·s−1 at baseline measurements in SQ were assessed before and after the protocols. (3) Results: BFR40 resulted in higher EMG alterations during and after exercise than the other protocols (p < 0.05). BFR40 also induced greater impairments in TMG-derived variables and BFR10 decreased contraction time. Higher blood lactate concentrations were found as the VL within the set increased. BFR0 and BFR10 showed significantly increased median frequencies in post-exercise MVIC. (4) Conclusions: High VL thresholds (BFR40) accentuated metabolic and neuromuscular stress, and produced increased alterations in muscles' mechanical properties. Low VL could potentiate post-exercise neuromuscular activity and muscle contractile properties. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine if women footballers have an increased lack of neuromuscular control of the knee joint after a concussion compared to a healthy cohort tested with tensiomyography (TMG). Forty-one female collegiate footballers were enrolled in this study from which there were 20 with a history of sports-related concussions (SRCs) and 21 control subjects. Results from the SRC group had significantly higher Tc (ms) (z = −5.478, p = 0.000) and significantly lower Dm (mm) (z = −3.835, p = 0.000) than the control group in the case of the rectus femoris muscle. The SRC group had significantly higher Tc (ms) (z = −2.348, p = 0.016) and significantly lower Dm (mm) (z = −4.776, p = 0.000) than the control group in the case of the vastus medialis muscle. The SRC group had significantly higher Tc (ms) (z = −5.400, p = 0.000) and significantly lower Dm (mm) (z = −4.971, p = 0.000) than the control group in the case of the vastus lateralis muscle. The SRC group had significantly higher Tc (ms) (z = −5.349, p = 0.000) than the control group in the case of the biceps femoris muscle response, whereas no significant difference was found in Dm (mm) (z = −0.198, p = 0.853) between the groups. The results of the current study may have implications for current practice standards regarding the evaluation and management of concussions and can add valuable information for knee prevention programs as well. [ABSTRACT FROM AUTHOR]

The inclusion of women canoe in the Olympic Games reflects the growth and development that women have ahead of them in this modality. Therefore, the aim of this study was to explore sex and performance level differences in muscle contractile properties through Tensiomyography (TMG), range of motion (ROM), strength, and canoe-specific functional electromechanical dynamometry (FEMD) performance and establish performance differences between international medalists and non-medalists. Twelve male and nine female canoeists from the Spanish and Portuguese national canoe teams were assessed through TMG, ROM, strength, and canoe-specific isometric and incremental FEMD tests. Few sex and performance level differences were found in TMG and ROM; however, significant sex differences were found in the strength and FEMD tests. Male canoeists had a greater Fmax in Leg Press, Pm and Pmax in canoe position cable row, 1RM bench press and bench pull, Fm and Fpeak canoe-specific isometric FEMD test and number of strokes, and Fpeak and Pmax on the incremental FEMD test than females. International medalists showed a lower time until reaching Vmax and Pmax in Leg Press on both sides and a greater number of strokes and Fpeak in the maximal incremental FEMD test than non-medalists. This study reinforces the utility of the use of TMG and FEMD for assessing and monitoring world-class athletes. [ABSTRACT FROM AUTHOR]

This study explored the effects of a 4-week circuit strength training with blood flow restriction on Taekwondo athletes. Six male athletes (age 20.6 ± 1.85, height 184.3 ± 7.63 cm, training duration 7.5 ± 2.07 years) were assessed for explosive strength, muscle recruitment, and sport-specific skills. The regimen encompassed evaluations of lower limb power, Isokinetic strength, force via electronic kicks, and Tensiomyography (TMG) measurements pre-and post-training. Outcomes revealed enhanced jumping abilities, improved knee muscles, and superior kicking skills. There was a notable increase in muscle fibre recruitment and a shift towards type II muscle fibres. Medial thigh muscle displacement showed a positive correlation with jump duration, while lateral thigh muscles indicated a connection with kick numbers. The regimen notably improved explosive power, muscle fibre distribution, and reduced muscle contraction times. Yet, no significant changes in lower limb bilateral symmetry or the link between TMG parameters and athletic prowess were observed. [ABSTRACT FROM AUTHOR]

Tensiomyography (TMG) has been described as an effective method for identifying differences in muscle response to athletic training stimuli. However, there is a lack of studies that evaluated changes in muscle contractile properties in response to anaerobic effort and related these changes to Wingate test parameters in more than one lower limb superficial muscle. The main contribution of this work is to evaluate changes in the contractile properties of muscles in response to anaerobic exercise. In a group of 20 physically active men, the body composition analysis was performed using a Tanita DC-360 device. The anaerobic effort was assessed by a Wingate test (30 s), and the contractile properties of muscles were measured using a TMG S2 device. The TMG parameters were measured in selected superficial muscles of the dominant lower limb. The study also calculated indices of the differences (d) and the size of the effect (r). An anaerobic effort in the form of the Wingate test resulted in greater stiffness (Dm) in the vastus lateralis muscle (p = 0.0365; r = 0.47) and a delayed response to stimulus (Td) in the vastus lateralis (p = 0.0239; r = 0.51) and vastus medialis (p = 0.0031; r = 0.66) muscles. The half relaxation time (Tr) (p = 0.0478; r = 0.44) and sustained contraction time (Ts) (p = 0.0276; r = 0.49) in the rectus femoris muscle were also increased. In contrast, a prolonged stimulus-response time (Td) with a decrease in sustained contraction time (Ts) was observed in the gastrocnemius lateralis (Td: p = 0.0054; r = 0.64 and Ts: p = 0.0012; r = 0.74) and gastrocnemius medialis (Td: p = 0.0229; r = 0.52 and Ts: p = 0.0054; r = 0.64) muscles. A significant decrease in contraction time (Tc) (p = 0.0051; r = 0.63) occurred only in the soleus muscle. In addition, significant correlations were shown between selected changes in contractile properties of muscle and parameters of the Wingate anaerobic test. Anaerobic exercise has a significant effect on changes in skeletal muscle contractility parameters. TMG is an effective method for identifying differences in muscle response to sports training stimuli. [ABSTRACT FROM AUTHOR]

Purpose: Gymnastics is a sport characterized by acrobatic and postural strength exercises that require great trunk muscles activation and control. Males and females can be characterized by different morphological and neuromuscular characteristics of such muscles, and this might be of importance for training and injury prevention. The aim of this study was to measure different aspects of trunk flexors and extensors characteristics in a sample of young female and male gymnasts. Methods: Twenty-eight sub-elite adolescent female (n = 14, 16 y, 14–17) and male (n = 14, 17 y, 14–18) gymnasts participated in this cross-sectional study. Tensiomyography was used to assess muscle contractile properties of the rectus abdominis (m.RA) and erector spinae (m.ES), while muscle thickness was assessed for abdominal muscles and lumbar multifidus (m.LM) with ultrasound. Flexors, extensors, and lateral endurance tests were performed. Results: Females presented smaller m.ES radial displacement (p < 0.001, pη2 = 0.535), smaller internal oblique thickness (p < 0.001, pη2 = 0.543), and shorter lateral endurance (p = 0.002, pη2 = 0.302). A significant side × sex interaction was found for the external oblique thickness (p = 0.004, pη2 = 0.276). Conclusion: Present findings report sex-based differences in abdominal and lumbar muscles characteristics and support the development of different sex-based training and rehabilitation protocols in adolescent gymnasts. [ABSTRACT FROM AUTHOR]

Background: The study aimed to examine alterations and imbalances in hamstring muscle contractile properties among young football players throughout their competitive season, and to understand how these changes might contribute to the risk of muscle injuries. Hamstring injuries are particularly common in football, yet the underlying causes and effective prevention methods remain unclear. Methods: The research involved 74 young footballers who were assessed before the season (pre-test) and after 12 weeks of training (post-test). To evaluate changes in hamstring muscle contractile properties, specifically the left and right biceps femoris (BF) and semitendinosus (ST), tensiomyography (TMG) parameters were utilized. Results: In comparison to the BF muscle, significant differences in time delay (Td) between the left and right sides in the post-test (p = 0.0193), and maximal displacement (Dm) between the left and right sides at the pre-test (p = 0.0395). However, significant differences in Dm were observed only in the left ST muscle between the pre- and post-tests (p = 0.0081). Regarding lateral symmetry, BF registered measurements of 79.7 ± 13.43 (pre-test) and 77.4 ± 14.82 (post-test), whereas ST showed measurements of 87.0 ± 9.79 (pre-test) and 87.5 ± 9.60 (posttest). Conclusions: These assessments provided TMG reference data for hamstring muscles in young footballers, both before the season and after 12 weeks of in-season training. The observed changes in the contractile properties and decrease in lateral symmetry of the BF in both tests suggest an increased risk of injury. [ABSTRACT FROM AUTHOR]

Background and Objectives: In many sports, maintaining muscle work at an optimal level despite fatigue is crucial. Therefore, it is essential to discover the most efficient way of recovery. This study aimed to evaluate and compare the acute effects of four different recovery methods on muscle neuromechanical properties. Materials and Methods: The research was conducted using a randomized, quasi-experimental, repeated-measures design. Fourteen healthy and active male students of the Faculty of Sport and Physical Education (age 25.1 ± 3.9 years) were included in this study. The tensiomyography was used to evaluate muscle responses after four different types of short-term recovery methods (passive rest, percussive mechanical, vibro-mechanical, and manual massage) on the rectus femoris muscle on four occasions: baseline, post fatigue, post recovery and prolonged recovery. Results: The ANOVA revealed that muscle fatigue decreased maximal vertical muscle displacement (Dm) and muscle contraction time (Tc) in post fatigue compared to the baseline. The most important finding shows that only the vibro-mechanical massage resulted in an increase in Tc in the prolonged recovery compared to the post fatigue (p = 0.028), whereas only manual massage showed no differences in Dm from the baseline in post-recovery (p = 0.148). Moreover, both manual and vibro-mechanical massages increased Dm and Tc in prolonged recovery, indicating no differences from the baseline (all p > 0.05), thus showing signs of muscle recovery. Percussion mechanical massage and passive rest did not show indices of muscle recovery. Conclusions: Manual massage could induce immediate positive changes in Dm by reducing muscle stiffness. In addition, vibro-mechanical and manual massage improved muscle tissue by rapidly returning Dm and Tc values to baseline at prolonged recovery measurement (5 min after the fatigue protocol). These findings can benefit sports practitioners, and physical therapists in developing the best recovery method after muscle fatigue. [ABSTRACT FROM AUTHOR]

Introduction: The electromechanical efficiency of skeletal muscle represents the dissociation between electrical and mechanical events within a muscle. It has been widely studied, with varying methods for its measurement and calculation. For this reason, the purpose of this literature review was to integrate the available research to date and provide more insights about this measure.Methods: A systematic search of the literature was performed across three online databases: PubMed, ScienceDirect, and SPORTDiscus. This yielded 1284 reports, of which 10 met the inclusion criteria. Included studies have used different methods to measure the electromechanical efficiency (EME) index, including electromyography (EMG), mechanomyography and tensiomyography (TMG).Results: The EME index was used to assess muscle conditions such as muscle atrophy, pain syndromes, or to monitor rehabilitation in patients with knee problems, fatigue and the effects of exercise and rehabilitation. TMG has been shown to be one of the most reliable methods to obtain the EME index, but its use precludes obtaining the index during voluntary muscle contractions.Conclusion: Standardizing the EME index is crucial for its diverse applications in clinical, sport, and rehabilitation contexts. Future research should prioritize standardization of measurement protocols for establishing the most repeatable, and reliable approach that can be used for inter-individual comparisons or for assessing an individual for multiple times over a longer period.Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023440333 Identifier: CRD42023440333.

Background The study aimed to examine alterations and imbalances in hamstring muscle contractile properties among young football players throughout their competitive season, and to understand how these changes might contribute to the risk of muscle injuries. Hamstring injuries are particularly common in football, yet the underlying causes and effective prevention methods remain unclear. Methods The research involved 74 young footballers who were assessed before the season (pre-test) and after 12 weeks of training (post-test). To evaluate changes in hamstring muscle contractile properties, specifically the left and right biceps femoris (BF) and semitendinosus (ST), tensiomyography (TMG) parameters were utilized. Results In comparison to the BF muscle, significant differences in time delay (Td) between the left and right sides in the post-test (p = 0.0193), and maximal displacement (Dm) between the left and right sides at the pre-test (p = 0.0395). However, significant differences in Dm were observed only in the left ST muscle between the pre- and post-tests (p = 0.0081). Regarding lateral symmetry, BF registered measurements of 79.7 ± 13.43 (pre-test) and 77.4 ± 14.82 (post-test), whereas ST showed measurements of 87.0 ± 9.79 (pre-test) and 87.5 ± 9.60 (post-test). Conclusions These assessments provided TMG reference data for hamstring muscles in young footballers, both before the season and after 12 weeks of in-season training. The observed changes in the contractile properties and decrease in lateral symmetry of the BF in both tests suggest an increased risk of injury.

(1) Background: The aim of this paper is to analyze the acute effects of different velocity loss (VL) thresholds during a full squat (SQ) with blood-flow restriction (BFR) on strength performance, neuromuscular activity, metabolic response, and muscle contractile properties. (2) Methods: Twenty strength-trained men performed four protocols that differed in the VL achieved within the set (BFR0: 0% VL; BFR10: 10% VL; BFR20: 20% VL; and BFR40: 40% VL). The relative intensity (60% 1RM), recovery between sets (2 min), number of sets (3), and level of BFR (50% of arterial occlusion pressure) were matched between protocols. Tensiomyography (TMG), blood lactate, countermovement jump (CMJ), maximal voluntary isometric SQ contraction (MVIC), and performance with the absolute load required to achieve 1 m·s−1 at baseline measurements in SQ were assessed before and after the protocols. (3) Results: BFR40 resulted in higher EMG alterations during and after exercise than the other protocols (p < 0.05). BFR40 also induced greater impairments in TMG-derived variables and BFR10 decreased contraction time. Higher blood lactate concentrations were found as the VL within the set increased. BFR0 and BFR10 showed significantly increased median frequencies in post-exercise MVIC. (4) Conclusions: High VL thresholds (BFR40) accentuated metabolic and neuromuscular stress, and produced increased alterations in muscles’ mechanical properties. Low VL could potentiate post-exercise neuromuscular activity and muscle contractile properties.

Purpose: Evolving investigative techniques are providing greater understanding about the early neuromuscular responses to resistance training among novice exercisers. The aim of this study was to investigate the time-course of changes in muscle contractile mechanics, architecture, neuromuscular, and strength adaptation during the first 6-weeks of lower-limb resistance training. Methods: Forty participants: 22 intervention (10 males/12 females; 173.48 ± 5.20 cm; 74.01 ± 13.13 kg) completed 6-week resistance training, and 18 control (10 males/8 females; 175.52 ± 7.64 cm; 70.92 ± 12.73 kg) performed no resistance training and maintained their habitual activity. Radial muscle displacement (Dm) assessed via tensiomyography, knee extension maximal voluntary contraction (MVC), voluntary activation (VA), corticospinal excitability and inhibition via transcranial magnetic stimulation, motor unit (MU) firing rate, and muscle thickness and pennation angle via ultrasonography were assessed before and after 2, 4, and 6-weeks of dynamic lower-limb resistance training or control. Results: After 2-weeks training, Dm reduced by 19–25% in the intervention group; this was before any changes in neural or morphological measures. After 4-weeks training, MVC increased by 15% along with corticospinal excitability by 16%; however, there was no change in VA, corticospinal inhibition, or MU firing rate. After 6-weeks training there was further MVC increase by 6% along with muscle thickness by 13–16% and pennation angle by 13–14%. Conclusion: Enhanced contractile properties and corticospinal excitability occurred before any muscle architecture, neural, and strength adaptation. Later increases in muscular strength can be accounted for by architectural adaptation. [ABSTRACT FROM AUTHOR]

BACKGROUND: Postactivation potentiation (PAP) enhances contractility of skeletal muscle whereas fatigue deteriorates it. Available evidence suggests that the two phenomena may express differently in endurance and power athletes. OBJECTIVE: To compare the patterns of change in knee muscle contractility induced by PAP and fatigue between endurance and power athletes. METHODS: Eleven endurance and ten power athletes (age: 18–33 years) performed isokinetic fatigue and isometric PAP protocols with knee extensors and flexors on computerised dynamometer. Tensiomyography (TMG) of the vastus medialis and semitendinosus muscle medialis was performed before the protocols and during a 10-min recovery. RESULTS: The changes in TMG profile were most pronounced in the vastus medialis of power athletes following the PAP protocol and least pronounced in the semitendinosus of the endurance athletes following the fatigue protocol. The differences between athlete types were most significant for the time-domain TMG parameters of vastus medialis. A significant correlation (r = 0.51–0.73) between the fatigue indices and changes in TMG parameters was observed for the vastus medialis muscle only. CONCLUSIONS: The results show that the TMG patterns of PAP and fatigue in the vastus muscle differ between endurance and power athletes. In this muscle, the changes in TMG parameters are also strongly associated with the degree of fatigue. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine if women footballers have an increased lack of neuromuscular control of the knee joint after a concussion compared to a healthy cohort tested with tensiomyography (TMG). Forty-one female collegiate footballers were enrolled in this study from which there were 20 with a history of sports-related concussions (SRCs) and 21 control subjects. Results from the SRC group had significantly higher Tc (ms) (z = −5.478, p = 0.000) and significantly lower Dm (mm) (z = −3.835, p = 0.000) than the control group in the case of the rectus femoris muscle. The SRC group had significantly higher Tc (ms) (z = −2.348, p = 0.016) and significantly lower Dm (mm) (z = −4.776, p = 0.000) than the control group in the case of the vastus medialis muscle. The SRC group had significantly higher Tc (ms) (z = −5.400, p = 0.000) and significantly lower Dm (mm) (z = −4.971, p = 0.000) than the control group in the case of the vastus lateralis muscle. The SRC group had significantly higher Tc (ms) (z = −5.349, p = 0.000) than the control group in the case of the biceps femoris muscle response, whereas no significant difference was found in Dm (mm) (z = −0.198, p = 0.853) between the groups. The results of the current study may have implications for current practice standards regarding the evaluation and management of concussions and can add valuable information for knee prevention programs as well.

The inclusion of women canoe in the Olympic Games reflects the growth and development that women have ahead of them in this modality. Therefore, the aim of this study was to explore sex and performance level differences in muscle contractile properties through Tensiomyography (TMG), range of motion (ROM), strength, and canoe-specific functional electromechanical dynamometry (FEMD) performance and establish performance differences between international medalists and non-medalists. Twelve male and nine female canoeists from the Spanish and Portuguese national canoe teams were assessed through TMG, ROM, strength, and canoe-specific isometric and incremental FEMD tests. Few sex and performance level differences were found in TMG and ROM; however, significant sex differences were found in the strength and FEMD tests. Male canoeists had a greater Fmax in Leg Press, Pm and Pmax in canoe position cable row, 1RM bench press and bench pull, Fm and Fpeak canoe-specific isometric FEMD test and number of strokes, and Fpeak and Pmax on the incremental FEMD test than females. International medalists showed a lower time until reaching Vmax and Pmax in Leg Press on both sides and a greater number of strokes and Fpeak in the maximal incremental FEMD test than non-medalists. This study reinforces the utility of the use of TMG and FEMD for assessing and monitoring world-class athletes.

Tensiomyography (TMG) has been described as an effective method for identifying differences in muscle response to athletic training stimuli. However, there is a lack of studies that evaluated changes in muscle contractile properties in response to anaerobic effort and related these changes to Wingate test parameters in more than one lower limb superficial muscle. The main contribution of this work is to evaluate changes in the contractile properties of muscles in response to anaerobic exercise. In a group of 20 physically active men, the body composition analysis was performed using a Tanita DC-360 device. The anaerobic effort was assessed by a Wingate test (30 s), and the contractile properties of muscles were measured using a TMG S2 device. The TMG parameters were measured in selected superficial muscles of the dominant lower limb. The study also calculated indices of the differences (d) and the size of the effect (r). An anaerobic effort in the form of the Wingate test resulted in greater stiffness (Dm) in the vastus lateralis muscle (p = 0.0365; r = 0.47) and a delayed response to stimulus (Td) in the vastus lateralis (p = 0.0239; r = 0.51) and vastus medialis (p = 0.0031; r = 0.66) muscles. The half relaxation time (Tr) (p = 0.0478; r = 0.44) and sustained contraction time (Ts) (p = 0.0276; r = 0.49) in the rectus femoris muscle were also increased. In contrast, a prolonged stimulus-response time (Td) with a decrease in sustained contraction time (Ts) was observed in the gastrocnemius lateralis (Td: p = 0.0054; r = 0.64 and Ts: p = 0.0012; r = 0.74) and gastrocnemius medialis (Td: p = 0.0229; r = 0.52 and Ts: p = 0.0054; r = 0.64) muscles. A significant decrease in contraction time (Tc) (p = 0.0051; r = 0.63) occurred only in the soleus muscle. In addition, significant correlations were shown between selected changes in contractile properties of muscle and parameters of the Wingate anaerobic test. Anaerobic exercise has a significant effect on changes in skeletal muscle contractility parameters. TMG is an effective method for identifying differences in muscle response to sports training stimuli.

Background: To examine the correlation between physical performance and muscle strength and the variables obtained from tensiomyography and myotonometry. Methods: Fifty-two older adults able to complete functional tests participated in this observational study. Variables of maximal radial muscle displacement (Dm) and contraction time (Tc) (using tensiomyography) and muscle stiffness (using myotonometry) of the rectus femoris and vastus lateralis muscles were assessed. Physical performance (Short Physical Performance Battery, Timed Up and Go, Five Times Sit to Stand, and walking speed), isometric knee extension strength, and grip strength were assessed. A correlation analysis was performed between all the variables. Results: A significant correlation between the Short Physical Performance Battery and the rectus femoris (rho = 0.491) and vastus lateralis Dm (rho = 0.329) was found. Significant correlations between the Five Times Sit to Stand Test and the Dm values of the rectus femoris (rho = −0.340) and Dm (rho = −0.304), and stiffness (rho = −0.345) in the vastus lateralis, were also found. No significant correlations were found between tensiomyography and myotonometry, the Timed Up and Go, and walking speed, nor between tensiomyography and myotonometry and grip strength or isometric knee extension strength. Conclusions: Functional tests should be prioritized in the assessment of older adults, but further research into muscle quality using technology is advisable. [ABSTRACT FROM AUTHOR]

Excessive amounts of intense training, without adequate recovery time, can overload the musculoskeletal, immune, and metabolic systems, resulting in a potentially negative effects on later exercise performance. During the competitive period, the ability to recover after intense training and competition is an important factor of success in soccer. The purpose of this study was to determine the effect of hamstring foam rolling on the knee muscle contractile properties in soccer players, after a sports-specific load. 20 male professional soccer players were included and contractile properties of the biceps femoris, rectus femoris, vastus medialis and vastus lateralis muscles were measured with tensiomyography, before and after a Yo-Yo interval test and after 5 × 45 s of hamstring foam rolling. Additionally, active and passive knee extensibility before and after the intervention were measured. A mixed linear model was performed to determine the differences between the mean values of the groups. The experimental group performed foam rolling, while the control was resting. Five repetitions of 45 s of hamstring foam rolling had no statistically significant effect (p > 0.05) on any of the measured muscles following the Yo-Yo interval test or foam rolling intervention. There were no statistically significant differences in delay time, contraction time and maximum muscle amplitude between groups. Active and passive knee extensibility did not differ between groups. It seems that foam rolling does not affect mechanical properties of the knee muscles or hamstring extensibility in soccer players, after a sports-specific load. • Foam rolling does not affect muscle contractility. • A researchers' dilemma is what to do about the clinical practices that are widely accepted without scientific basis. • Foam rolling does not affect hamstring extensibility in soccer players, after a sports-specific load. [ABSTRACT FROM AUTHOR]

Lumbar stabilization exercises (LSE) lead to high levels of erector spinae muscle (ESM) activation, which has a positive effect on improving physical function. The purpose of this study is to identify factors explaining changes in muscle strength after 7 weeks of LSE and to evaluate changes in stiffness and contraction of the ESM. All participants (male: n = 42, age = 28.26 ± 10.97) were assessed for 60°/s isokinetic extensor muscle strength and tension using a tensiomyography (TMG) and isokinetic device before and after LSE. Maximum displacement (Dm) and average velocity up to 90% Dm (Vc 90) were significantly different before and after LSE. Additionally, participants' 60°/s isokinetic extensor strength was significantly higher after exercise. A regression analysis was conducted to test the explanatory power of the variables, and positive results were obtained in the increase in extensor strength before and after Vc 90 and LSE. Furthermore, statistical significance was set at p < 0.05. After LSE, the increase in 60°/s isokinetic extensor strength and ESM's Dm and Vc 90 can be interpreted as positive changes post-exercise in endurance muscles with a higher percentage of type I fibers. Our results can contribute to predicting the long-term exercise effect in sedentary workers and developing an individualized strategic exercise program. [ABSTRACT FROM AUTHOR]

Background and Objectives: In many sports, maintaining muscle work at an optimal level despite fatigue is crucial. Therefore, it is essential to discover the most efficient way of recovery. This study aimed to evaluate and compare the acute effects of four different recovery methods on muscle neuromechanical properties. Materials and Methods: The research was conducted using a randomized, quasi-experimental, repeated-measures design. Fourteen healthy and active male students of the Faculty of Sport and Physical Education (age 25.1 ± 3.9 years) were included in this study. The tensiomyography was used to evaluate muscle responses after four different types of short-term recovery methods (passive rest, percussive mechanical, vibro-mechanical, and manual massage) on the rectus femoris muscle on four occasions: baseline, post fatigue, post recovery and prolonged recovery. Results: The ANOVA revealed that muscle fatigue decreased maximal vertical muscle displacement (Dm) and muscle contraction time (Tc) in post fatigue compared to the baseline. The most important finding shows that only the vibro-mechanical massage resulted in an increase in Tc in the prolonged recovery compared to the post fatigue (p = 0.028), whereas only manual massage showed no differences in Dm from the baseline in post-recovery (p = 0.148). Moreover, both manual and vibro-mechanical massages increased Dm and Tc in prolonged recovery, indicating no differences from the baseline (all p > 0.05), thus showing signs of muscle recovery. Percussion mechanical massage and passive rest did not show indices of muscle recovery. Conclusions: Manual massage could induce immediate positive changes in Dm by reducing muscle stiffness. In addition, vibro-mechanical and manual massage improved muscle tissue by rapidly returning Dm and Tc values to baseline at prolonged recovery measurement (5 min after the fatigue protocol). These findings can benefit sports practitioners, and physical therapists in developing the best recovery method after muscle fatigue.

Objective: The purpose of this study is a comparison of skeletal muscle characteristics in Slovenian gymnasts assessed by TMG and values of contraction properties of muscles, lateral symmetries, and the effect of aging on selected contraction properties of skeletal muscles in men's artistic gymnastics (MAG); women's artistic gymnastics (WAG) and rhythmic gymnastics (RG). This study is the first larger study to use the TMG method and in which top athletes from artistic and rhythmic gymnastics participated. Materials and Methods: A survey of 81 athletes from different disciplines was conducted as follows: MAG (n = 26), WAG (n = 28), and RG (n = 27). The athletes' average age was 15.41 ± 5.03 years. In this study, the contraction times of ten skeletal muscles for Slovenian gymnasts on the right and left sides of the body were compared: M. Biceps brachii, M. Triceps brachii, M. Biceps femoris, M. Erector spinae, M. Gastrocnemius lateralis, M. Gastrocnemius medialis, M. Rectus femoris, M. Tibialis anteriror, M Vastus lateralis, M. Vastus medialis. Results: In MAG, a statistically significant correlation between age and contraction time was found for m. VL and m. VM. In WAG, was found for m. GM. In RG was found for m. TA and m VL for all at p < 0.01. Conclusions: A comparison between the left and the right side body shows a slight asymmetry. With TMG, we can assess the discipline's demands and help improve gymnasts' performances along with the safety of training. Tensiomyography has a high predictive ability to discriminate between the left and right sides of the body functionally. [ABSTRACT FROM AUTHOR]

Background: Tensiomyography (TMG) is a non-invasive instrument for measuring mechanical muscle contraction characteristics and measuring the maximum displacement of the muscle belly in the radial direction with respect to the muscle and the time needed to achieve this from electrical stimulation. There have been only been a reports of TMG in healthy adults. A systematic review of TMG reported a low proportion of female participants, with a small sample size. Therefore, it is unclear whether there is a difference in TMG parameters according to sex and between dominant and non-dominant feet. Furthermore, the relationship between TMG parameters and evaluations commonly used in clinical practice has not been clarified. This study aimed to clarify the characteristics of muscle contraction of the rectus femoris using TMG according to sex among healthy college students and its relationship with muscle function evaluation, such as lower limb muscle mass and muscle strength. Methods: This cross-sectional study included 91 healthy university students (18-24 years). Five tools were used: TMG, lower-limb muscle mass, rectus femoris thickness, isometric knee joint extension torque, and thigh circumference. Each parameter was compared by the generalized linear mixed model (GLMM) and Bonferroni's multiple comparison test, with sex as the without-subject factor and dominant/non-dominant foot as the within-subject factor. The correlation between the TMG parameters and other parameters was examined using Pearson's correlation coefficient for both males and females. Results: The results of the GLMM, in terms of the TMG parameters, an interaction was observed for maximum displacement (Dm); in the results of the multiple comparison test, Dm for the non-dominant leg was significantly lower in females than in males. A main effect and interaction were not observed for delay time (Td) and contraction time (Tc) by sex, dominant foot, or non-dominant foot. There was a main effect of sex on muscle function evaluation parameters (1 = 0.05). The correlation between TMG parameters for males and females and lower limb muscle mass, muscle thickness, joint torque, and thigh circumference were significantly correlated with some TMG parameters, lower limb muscle mass and muscle thickness (1 = 0.05). The absolute value of the correlation coefficient was low overall (0.20-0.38). Conclusion: In healthy college students, TMG parameters for the rectus femoris showed sex differences in Dm, and there was a weak correlation between TMG parameters and lower limb muscle mass. TMG parameter evaluation may indicate a different function compared to the traditional muscle function assessment used in clinical practice. When using the Dm of the TMG as an evaluation battery for the rectus femoris muscle, it is important to consider sex-related differences. [ABSTRACT FROM AUTHOR]

Introduction: Cold exposures impair neuromuscular function.1 Tensiomyography (TMG) non-invasively assesses muscle contractile properties with electrical stimulation.2 Until present, there are no reports to clarify icing effects on muscle contractile properties with TMG. Objective: To investigate the effects of icing on muscle temperature and contractile properties. Methods: Eight healthy males (age: 22.9 ± 2.2 years) participated in this study. Each participant completed two conditions (icing and control) each for 15 minutes on separate days in a random order. Icing was applied on the right gastrocnemius muscles. Muscle temperature was measured at gastrocnemius lateralis. Muscle contractile properties of the gastrocnemius medialis were measured using Tensiomyography (TMG--100). The stimulation intensity was increased gradually to 20 mA, reaching a plateau in the twitch response curve. TMG parameters, including maximal radial displacement (Dm), delay time (Td), contraction time (Tc), and velocity of contraction (Vc), were then measured from the maximal twitch response. Two-way repeated-measures ANOVA was performed, and the Bonferroni test was used for post-hoc comparisons. Results: In the icing condition, muscle temperature were significantly decreased (Pre: 34.2 ± 0.9 °C; Post: 28.6 ± 2.7 °C, p < 0.001). Neuromuscular properties were shown with Td (Pre: 20.2 ± 1.1 ms; Post: 23.9 ± 1.4 ms, p < 0.001), Tc (Pre: 20.9 ± 2.1 ms; Post: 23.2 ± 2.6 ms, p = 0.021) and Vc (Pre: 0.087 ± 0.024 mm/ms; Post: 0.076 ± 0.021 mm/ms, p < 0.001) were significantly impaired after icing. However, no significant changes with Dm in icing condition (p = 0.206) and muscle temperature and TMG parameters in control condition (p = 0.092-0.994). Conclusion: Icing temporally impairs muscle contractile properties, but the maximal radial displacement remains unchanged. The present results suggest that icing may negatively affect neuromuscular properties without altering mechanical properties with the muscle contraction. [ABSTRACT FROM AUTHOR]

Abián-Vicén, J, Martínez, F, Jiménez, F, and Abián, P. Effects of eccentric single-leg decline squat training performed with different execution times on maximal strength and muscle contraction properties of the knee extensor muscles. J Strength Cond Res 36(11): 3040–3047, 2022—The eccentric phase of the single-leg decline squat (SLDSe) has been described as a method to maximally load the knee extensor and has been used as an easy and effective rehabilitation exercise for patellar tendinopathy. The purpose of this study was to examine the impact of 6-week SLDSe training with 2 technical execution times on changes related to strength and muscle contractile properties. Thirty-six healthy volunteers were randomly divided into 3 groups: a control group (CG, n = 13, no training), a slow training group (n = 11, SLDSe in 6 seconds), and a fast training group (n = 12, SLDSe in 3 seconds). Subjects completed a 6-week SLDSe training program (80% of eccentric one repetation maximum [1RM]) 3 days a week. Pre, post, and 6-week follow-up of maximal dynamic and isometric strength and muscle contractile properties were assessed. After 6 weeks, training maximal loads showed a significant increase (p < 0.05) in 1RM of the SLDSe (∼92–95%), the concentric peak torque at 180°·s−1 (∼38%) and 60°·s−1 (∼25%), and the extension isometric peak torque (∼12%), with no differences between both experimental groups. Moreover, a decrease (p < 0.05) was found in the contraction time of the vastus medialis (VM) and the response time of the 3 analyzed quadriceps muscles. After the 6-week detraining period, there was a decrease in strength in all tests and in both experimental groups (1RM = 28–37%, isometric and isokinetic tests = 7–17%) and all contractile properties returned to baseline, except for the response time of the vastus lateralis in the fast training group and the contraction time of the VM in the STG. In conclusion, the SLDSe training protocol produced significant increases in muscle strength, showing important neuromuscular changes regardless of the technical execution time. It was also found that the training reduced the response and contraction time of the knee extensor musculature. [ABSTRACT FROM AUTHOR]

Piqueras-Sanchiz, F, Cornejo-Daza, PJ, Sánchez-Valdepeñas, J, Bachero-Mena, B, Sánchez-Moreno, M, Martín-Rodríguez, S, García-García, Ó, and Pareja-Blanco, F. Acute mechanical, neuromuscular, and metabolic responses to different set configurations in resistance training. J Strength Cond Res 36(11): 2983–2991, 2022—The aim of this study was to investigate the effect of set configuration on mechanical performance, neuromuscular activity, metabolic response, and muscle contractile properties. Sixteen strength-trained men performed 2 training sessions in the squat exercise consisting of (a) 3 sets of 8 repetitions with 5 minutes rest between sets (3 × 8) and (b) 6 sets of 4 repetitions with 2 minutes rest between sets (6 × 4). Training intensity (75% one repetition maximum), total volume (24 repetitions), total rest (10 minutes), and training density were equalized between protocols. A battery of tests was performed before and after each protocol: (a) tensiomyography (TMG), (b) blood lactate and ammonia concentration, (c) countermovement jump, and (d) maximal voluntary isometric contraction in the squat exercise. Force, velocity, and power output values, along with electromyography data, were recorded for every repetition throughout each protocol. The 6 × 4 protocol resulted in greater mechanical performance (i.e., force, velocity, and power) and lower neuromuscular markers of fatigue (i.e., lower root mean square and higher median frequency) during the exercise compared with 3 × 8, particularly for the last repetitions of each set. The 3 × 8 protocol induced greater lactate and ammonia concentrations, greater reductions in jump height, and greater impairments in TMG-derived velocity of deformation after exercise than 6 × 4. Therefore, implementing lower-repetition sets with shorter and more frequent interset rest intervals attenuates impairments in mechanical performance, especially in the final repetitions of each set. These effects may be mediated by lower neuromuscular alterations, reduced metabolic stress, and better maintained muscle contractile properties. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse the effect of an individual training programme based on the tensiomyography results in the contractile properties of the knee flexor muscle with football players. Thirty-four subjects were recruited and assigned to an experimental (EG) or control group (CG). The contraction time and the muscle displacement measured by tensiomyography were assessed on two occasions: pre-time (middle of the competitive season, January) and post-time 8 weeks later. The training programme aimed to improve muscle tone and explosiveness according to the individual needs of each player. There was a significant interaction between time (assessment points) × group (EG vs. CG) × muscle in multivariate analysis. The findings confirmed that mechanical and neuromuscular characteristics changed over time and varied with the individual training programme (EG vs. CG) and the muscle being analysed. The 90° change of direction worsens the execution time in the control group and is maintained in the experimental group. The individual training programme, based on the tensiomyography results, showed improvements in the contractile properties in the muscles. Football coaches could use the programme to improve neuromuscular characteristics that improve performance and reduce the risk of muscle injury. [ABSTRACT FROM AUTHOR]

Background. Studies on motor imagery (MI) practice based on different designs and training protocols have reported changes in maximal voluntary contraction (MVC) strength. However, to date, there is a lack of information on the effects of MI training on contractile properties of the trained muscle. Methods. Forty-five physically active sport science students (21 female) were investigated who trained three times per week over a 4-week period in one of three groups: An MI group conducted MI practice of maximal isometric contraction of the biceps brachii; a physical exercise (PE) group physically practiced maximal isometric contractions of the biceps brachii in a biceps curling machine; and a visual imagery (VI) group performed VI training of a landscape. A MVC test of the arm flexors was performed in a biceps curling machine before and after 4 weeks of training. The muscular properties of the biceps brachii were also tested with tensiomyography measurements (TMG). Results. Results showed an interaction effect between time and group for MVC (pD 0:027, -2 D 0.17), with a higher MVC value in the PE group (15.9%) compared to the VI group (11.3%) (pD0:013). MVC did not change significantly in the MI group (12.1%). Analysis of muscle contractility via TMG did not show any interaction effects neither for maximal radial displacement (pD0:394, -2 D 0.05), delay time (pD0:79, -2 D 0.01) nor contraction velocity (pD0:71, -2 D 0.02). Conclusion. In spite of MVC-related changes in the PE group due to the interventions, TMGmeasurements were not sensitive enough to detect concomitant neuronal changes related to contractile properties. [ABSTRACT FROM AUTHOR]

The aim of this study was to monitor seasonal changes in the mechanical and neuromuscular characteristics of the knee flexor muscles with tensiomyography, the biceps femoris (BF) and semitendinosus (ST) muscles, of 27 soccer players. All male professional soccer players (age 25 ± 4 years) were measured at the beginning of the preseason (second week) and in the competitive season (10 weeks later). The variables contraction time (Tc) and muscle displacement (Dm) showed significant differences in some muscles, and in others they indicated a tendency to change. In general, the BF improved (more explosive and better muscle tone) and the ST worsened (slower and worse muscle tone) its values during the season. The findings of this study suggest that usual daily soccer training and weekly competition might produce antagonistic changes between the knee flexor muscles. [ABSTRACT FROM AUTHOR]

Background: Cardiovascular diseases are the world's number one cause of death, with exceeding psychosocial stress load being considered a major risk factor. A stress management technique that has repeatedly shown positive effects on the cardiovascular system is the Transcendental Meditation (TM) technique. The present pilot study aimed to investigate the potential effect of TM on the recovery of cardiac patients. Objectives: We hypothesized that practicing TM in patients undergoing a 4-week cardiac rehabilitation program augments the recovery of cardiovascular parameters and reduces skeletal muscle tone after rehabilitation. Methods: Twenty cardiac patients were recruited and randomly assigned to either the control or the TM group. Cardiovascular parameters were assessed with the Task Force Monitor (TFM) and skeletal muscle contractile properties by Tensiomyography during a sit-stand test, performed at the beginning and end of a 4-week in-patient rehabilitation program. Results: Systolic blood pressure (SBP) was significantly lower after 4 weeks of cardiac rehabilitation, while the RR-interval (RRI) significantly increased. At the skeletal muscle level, the contraction time and maximal displacement increased, though only in the gastrocnemius medialis and biceps femoris muscles and not in vastus lateralis. Group interactions were not observed for hemodynamic parameters nor for muscle contractile properties. Discussion: Although significant improvements in hemodynamic and muscular parameters were observed after 4 weeks of rehabilitation, we could not provide evidence that TM improved rehabilitation after 4 weeks. TM may unfold its effects on the cardiovascular system in the longer term. Hence, future studies should comprise a long-term follow-up. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate how the relationship between resistance training-induced hypertrophy, strength, and passive contractile adaptations is affected by contraction duration. Twenty university students (11 males) were randomly assigned to either the fast eccentric/fast concentric phase group (F/F; 1 s both phases) or the slow eccentric/fast concentric phase group (S/F; 4 s and 1 s, respectively). Both experimental groups completed a 7-week biceps curl training programme with a total of 14 sessions (2 days/week). Elbow flexor muscle thickness (MT), one-repetition maximum (1RM), and tensiomyographic (TMG) parameters (radial displacement-Dm and contraction time-Tc) were assessed. The percentage change (∆) in MT correlated significantly with the ∆1RM only in the S/F group (r = 0.712, p < 0.05). Both groups demonstrated significant negative associations between ∆MT and ∆Dm (r = 0.717-0.760, p < 0.01). Conversely, no significance was found between ∆MT and ∆Tc (F/F: r = -0.398, p = 0.255; S/F: r = 0.410, p = 0.239), ∆1RM and ∆Tc (F/F: r = -0.278, p = 0.436; S/F: r = 0.223, p = 0.536), nor ∆1RM and ∆Dm (F/F: r = - 0.131, p = 0.719; S/F: r = - 0.351, p = 0.320). The main findings indicate that the relationship between hypertrophy and strength gains is significantly stronger when resistance training was paced with slower eccentric contractions comparing to fast ones. On the other hand, reduced Dm values indicate increase in MT regardless of contraction duration, while strength gains are not correlated with corresponding TMG changes. [ABSTRACT FROM AUTHOR]

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Background Studies on motor imagery (MI) practice based on different designs and training protocols have reported changes in maximal voluntary contraction (MVC) strength. However, to date, there is a lack of information on the effects of MI training on contractile properties of the trained muscle. Methods Forty-five physically active sport science students (21 female) were investigated who trained three times per week over a 4-week period in one of three groups: An MI group conducted MI practice of maximal isometric contraction of the biceps brachii; a physical exercise (PE) group physically practiced maximal isometric contractions of the biceps brachii in a biceps curling machine; and a visual imagery (VI) group performed VI training of a landscape. A MVC test of the arm flexors was performed in a biceps curling machine before and after 4 weeks of training. The muscular properties of the biceps brachii were also tested with tensiomyography measurements (TMG). Results Results showed an interaction effect between time and group for MVC (p = 0.027, η2 = 0.17), with a higher MVC value in the PE group (Δ5.9%) compared to the VI group (Δ −1.3%) (p = 0.013). MVC did not change significantly in the MI group (Δ2.1%). Analysis of muscle contractility via TMG did not show any interaction effects neither for maximal radial displacement (p = 0.394, η2 = 0.05), delay time (p = 0.79, η2 = 0.01) nor contraction velocity (p = 0.71, η2 = 0.02). Conclusion In spite of MVC-related changes in the PE group due to the interventions, TMG measurements were not sensitive enough to detect concomitant neuronal changes related to contractile properties.

Purpose: The neuromuscular system of soccer players is a key factor in their competitive performance, as it determines a player's immediate force response, reactivity and running speed during matches. The neuromuscular system has recently begun to be analyzed by tensiomyography (TMG). This study's primary aim was to generate normative data of the mechanical and neuromuscular profile for the knee extensor and flexor muscles. Method: This study used a cross-sectional study of 83 professional soccer players from three Saudi Premier League teams at the start of the preseason period. TMG was used to measure the radial muscle belly displacement in the knee extensor and flexor muscles in both legs. Results: The results suggest that the highest degree of symmetry corresponded to the vastus medialis (83.7 ± 14.3%) and the lowest to the biceps femoris (76.1 ± 10.9%). No statistical difference was found between the dominant and non-dominant muscles, or between on-field player positions across all four tested muscles. Conclusion: The study presented normative data of a convenience sample of Saudi professional soccer players and observed that the highest asymmetry was seen in the vastus medialis and the lowest asymmetry in the biceps femoris.

Introduction: Because healthy behaviors learned early in life are more likely to be maintained during adulthood, we aimed to investigate longitudinal changes of participants that were regularly involved in extracurricular sport activities (athletes; N = 7; 4 boys) and those that were not (non-athletes, N = 6; 3 boys) Methods: Participants of both groups were invited for re-assessment at the age of 27, in 2019, 12 years after they participated in a 5-year longitudinal study as adolescents (9–14 years of age, in the period 2001‒07). We investigated vastus lateralis (VL) and biceps femoris (BF) contractile properties (tensiomyography), maximal running speed (photocells), anthropometric measures (bioimpedance), maximal vertical jumping height (squat and countermovement jumps on a ground reaction force plate), and lifestyle characteristics (GPAQ and EHIS surveys). Results: Based on Cohen’s d effect size we found that athletes have lower body mass index, higher maximal running speed, better maximal vertical jumping height, and shorter BF contraction time, not found in VL, compared to non-athletes. Furthermore, athletes also exhibit healthier lifestyle characteristics such as lower sedentary time and higher daily energy expenditure than non-athletes. Athletes follow diet regimens consisting of more regular meals with more protein and indulge less in health-risk behavior (smoking and alcohol consumption). However, the self-perception of health and quality of life was lower in athletes than in non-athletes. Conclusion: EU regulations and the beginning of the COVID-19 pandemics prevented us from conducting a study on a more representative sample. Nevertheless, we could confirm that regular sport participation yields better physical performance and a healthier lifestyle but could also have a negative impact on health (injuries) and quality of life.

Background: To examine the correlation between physical performance and muscle strength and the variables obtained from tensiomyography and myotonometry. Methods: Fifty-two older adults able to complete functional tests participated in this observational study. Variables of maximal radial muscle displacement (Dm) and contraction time (Tc) (using tensiomyography) and muscle stiffness (using myotonometry) of the rectus femoris and vastus lateralis muscles were assessed. Physical performance (Short Physical Performance Battery, Timed Up and Go, Five Times Sit to Stand, and walking speed), isometric knee extension strength, and grip strength were assessed. A correlation analysis was performed between all the variables. Results: A significant correlation between the Short Physical Performance Battery and the rectus femoris (rho = 0.491) and vastus lateralis Dm (rho = 0.329) was found. Significant correlations between the Five Times Sit to Stand Test and the Dm values of the rectus femoris (rho = −0.340) and Dm (rho = −0.304), and stiffness (rho = −0.345) in the vastus lateralis, were also found. No significant correlations were found between tensiomyography and myotonometry, the Timed Up and Go, and walking speed, nor between tensiomyography and myotonometry and grip strength or isometric knee extension strength. Conclusions: Functional tests should be prioritized in the assessment of older adults, but further research into muscle quality using technology is advisable.

Purpose: The hamstrings (HS) muscle group plays a fundamental role in maintaining knee stability, thus contributing to the prevention and rehabilitation of lower limb musculoskeletal injuries. However, little is known about HS structural and functional adaptations after periods of prolonged inactivity. Our purpose was to investigate the HS morphological and contractile properties changes during 10 d of bed rest (BR). Methods: Ten young healthy males underwent a 10-d BR. HS cross-sectional area (CSA) (at 30%, 50%, and 70% of femur length) and biceps femoris long head (BFlh) architecture were assessed by ultrasound imaging after 0 d (BR0), 2 d (BR2), 4 d (BR4), 6 d (BR6), and 10 d (BR10) of BR, whereas BFlh contractile properties (radial twitch displacement [Dm] and contraction time [Tc]) were evaluated at the same time points by tensiomyography. HS muscle volume was assessed by magnetic resonance imaging at BR0 and BR10. Results: A reduction in muscle volume was observed in BFlh (P = 0.002; Δ = −3.53%), biceps femoris short head (P = 0.002; Δ = −3.54%), semitendinosus (P = 0.002; Δ = −2.63%), semimembranosus (P = 0.002; Δ = −2.01%), and HS pooled together (P < 0.001; Δ = −2.78%). Early changes in CSA were detected at 30% femur length already at BR6 for BFlh (P = 0.009; Δ = −2.66%) and biceps femoris short head (P = 0.049; Δ = −1.96%). We also found a reduction in fascicle length at BR6 (P = 0.035; Δ = −2.44%) and BR10 (P < 0.001; Δ = −2.84%). Dm and Tc increased at BR2 (P = 0.010; Δ = 30.0%) and B10 (P = 0.019; Δ = 19.7%), respectively. Conclusions: Despite being a nonpostural muscle group, HS exhibited a moderate reduction in muscle dimensions in response to a short unloading period. Small changes in BFlh fascicle length were also observed, accompanied by alterations in BFLh contractile properties. These HS modifications should not be ignored from a clinical perspective. [ABSTRACT FROM AUTHOR]

Merrigan, JJ, Jones, MT, Malecek, J, Padecky, J, Omcirk, D, Xu, N, Peñailillo, L, and Tufano, JJ. Comparison of traditional and rest-redistribution sets on indirect markers of muscle damage following eccentric exercise. J Strength Cond Res 36(7): 1810–1818, 2022—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. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate the efficacy of core training in the swimming performance and neuromuscular properties of young swimmers. Methods: Eighteen healthy male swimmers (age: 13 ± 2 years, height: 159.6 ± 14.5 cm, weight: 48.7 ± 12.4 kg) were recruited from the Public Authority for Sports swimming pool in Dammam and randomly assigned to the experimental and control groups. The experimental group performed a six-week core-training program consisting of seven exercises (three times/week) with regular swimming training. The control group maintained its regular training. Swimming performance and neuromuscular parameters were measured pre- and post-interventions. Results: The experimental group benefitted from the intervention in terms of the 50 m swim time (−1.4 s; 95% confidence interval −2.4 to −0.5) compared with the control group. The experimental group also showed improved swimming velocity (+0.1 m.s−1), stroke rate (−2.8 cycle.min−1), stroke length (+0.2 m.cycle−1), stroke index (+0.4 m2·s−1), total strokes (−2.9 strokes), and contraction time for erector spinae (ES; −1.5 ms), latissimus dorsi (LD; −7 ms), and external obliques (EO; −1.9 ms). Maximal displacement ES (DM-ES) (+3.3 mm), LD (0.5 mm), and EO (+2.2 mm) were compared with the baseline values for the experimental group, and TC-ES (5.8 ms), LD (3.7 ms), EO (2.5 ms), DM-ES (0.2 mm), LD (−4.1 mm), and EO (−1.0 mm) were compared with the baseline values for the control group. The intergroup comparison was statistically significant (p < 0.05; DM-ES p > 0.05). Conclusion: The results indicate that a six-week core-training program with regular swimming training improved the neuromuscular properties and the 50 m freestyle swim performance of the experimental group compared with the control group. [ABSTRACT FROM AUTHOR]

Lumbar stabilization exercises (LSE) lead to high levels of erector spinae muscle (ESM) activation, which has a positive effect on improving physical function. The purpose of this study is to identify factors explaining changes in muscle strength after 7 weeks of LSE and to evaluate changes in stiffness and contraction of the ESM. All participants (male: n = 42, age = 28.26 ± 10.97) were assessed for 60°/s isokinetic extensor muscle strength and tension using a tensiomyography (TMG) and isokinetic device before and after LSE. Maximum displacement (Dm) and average velocity up to 90% Dm (Vc 90) were significantly different before and after LSE. Additionally, participants’ 60°/s isokinetic extensor strength was significantly higher after exercise. A regression analysis was conducted to test the explanatory power of the variables, and positive results were obtained in the increase in extensor strength before and after Vc 90 and LSE. Furthermore, statistical significance was set at p < 0.05. After LSE, the increase in 60°/s isokinetic extensor strength and ESM’s Dm and Vc 90 can be interpreted as positive changes post-exercise in endurance muscles with a higher percentage of type I fibers. Our results can contribute to predicting the long-term exercise effect in sedentary workers and developing an individualized strategic exercise program.

Simple Summary: The hamstring muscle group is the most frequently injured muscle group in non-contact muscle injuries involving high-speed running sports. The biceps femoris (BF) muscle has the highest injury incidence. Clinical assessments and magnetic resonance imaging (MRI) are routinely used to diagnose a given injury. We tested the possibilities of a new technology—tensiomyography—as a potential screening test (diagnostic and classification purposes) to assess the functional differences between injured and non-injured BF muscles. The results show that tensiomyography has a high predictive ability to discriminate between injured and non-injured BF non-invasively and functionally and that it can be reliably used as a complementary screening test in the diagnosis of BF injuries. The hamstring muscle group is the most frequently injured muscle group in non-contact muscle injuries in sports involving high-speed running. A total of 84% of hamstring injuries affect the biceps femoris (BF) muscle. Clinical assessments and magnetic resonance imaging (MRI) are routinely used for diagnosis and plan management. MRI-negative scans for clinically diagnosed hamstring injuries range from 14% to 45%. We tested the hypothesis that the functional differences between injured and non-injured BF assessed by tensiomyography can be used for diagnostic and classification purposes. We compared an injured group of 53 international-level soccer players and sprinters with 53 non-injured international-level soccer players and sprinters of both sexes. Comparing the injured vs. non-injured athletes and the left vs. right side in all of the athletes, we used the percentage of absolute differences in the BF contraction time (Tc) to classify non-injured and injured BF muscles. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) and the precision–recall curve (PRC) were used to measure the classification accuracy and to identify cut-off limits using the Tc differences. There was a very high ROC AUC value of 0.981 (SE = 0.009, p < 0.000), with 98.11% of the injured muscles being correctly classified (cut-off point 12.50% on Tc differences), and an AUPRC value of 0.981, with association classification criteria at >9.87. Tensiomyography has a high predictive ability to discriminate between injured and non-injured BF non-invasively and functionally. [ABSTRACT FROM AUTHOR]