Effects Of Muscle Strength Training Research Articles

Effects of muscle strength training combined with aerobic training versus aerobic training alone on cardiovascular disease risk indicators in patients with coronary artery disease: a systematic review and meta-analysis of randomised clinical trials

ObjectiveTo compare the effects of aerobic training combined with muscle strength training (hereafter referred to as combined training) to aerobic training alone on cardiovascular disease risk indicators in patients with...

Effects of blood flow restriction therapy in patients with knee osteoarthritis: protocol for an overview of systematic reviews.

Osteoarthritis (OA) is the most common and prevalent musculoskeletal disease associated with population aging, negatively impacting function and quality of life. A consequence of knee OA is quadriceps muscle weakness. Musculoskeletal rehabilitation using low load exercises, associated with Blood Flow Restriction (BFR) may be a useful alternative to high load exercises when those cannot be tolerated. Several systematic reviews have reported inconclusive results due to discrepancies in study findings, heterogeneity of results, evaluated time points, and research questions explored. To perform an overview of systematic reviews with meta-analyses, synthesizing the most recent evidence on the effects of muscle strength training with BFR for knee OA. Systematic reviews that include primary controlled and randomized clinical trials will be considered for inclusion. Articles will be considered only if they present a clear and reproducible methodological structure, and when they clearly demonstrate that a critical analysis of the evidence was carried out using instrumented analysis. Narrative reviews, other types of review, overviews of systematic reviews, and diagnostic, prognostic and economic evaluation studies will be excluded. Studies must include adults aged 40 years and older with a diagnosis of knee OA. Two authors will perform an electronic search with guidance from an experienced librarian. The following databases will be searched: PubMed via MEDLINE, Embase, CENTRAL (Cochrane Central Register of Controlled Trials), PEDro, Cumulative Index to Nursing and Allied Health Literature (CINAHL) via EBSCO host, Web of Science, and the gray literature. The search strategy used in the databases will follow the acronym PICOS (population, intervention, comparison, outcome, and study design). Screening (i.e., titles and abstracts) of studies identified by the search strategy will be selected using Rayyan (http://rayyan.qcri.org). The quality assessment will be performed using the "Assessment of Multiple Systematic Reviews" (AMSTAR-2) tool. PROSPERO, CRD42022367209.

ANÁLISE DE ESTRATÉGIAS ALTERNATIVAS PARA RECUPERAÇÃO FÍSICA E FORÇA MUSCULAR APÓS O TREINO DE BASQUETEBOL

ABSTRACT Introduction: The need to increase muscle strength and optimize physical recovery is essential for athletes’ maximum performance in basketball competitions. However, alternative interventions are still little explored for the physical recovery process. Objective: Explore the effect of muscle strength training in basketball and alternative strategies for physical recovery. Methods: After basketball strength training, the control group adopted the traditional stretching method, while the experimental group combined yoga and music for a gradual warm-up and body relaxation. In this process, we measured changes in blood lactate content during exercise. Within 5 minutes, 15 minutes, and 30 minutes after exercise was used to analyze the effect of muscle recovery between the groups. Results: Muscle strength training can comprehensively improve performance indicators of all aspects of basketball. Still, many biochemical parameters of muscle strength, especially of the shoulder and back, showed no significant effect in the control group. The relative total work (TWP), average power (AP), and relative average power (APP) indicators showed a significant impact after the alternative intervention in the experimental group. Conclusion: Muscle strength training can effectively improve multiple qualities in athletes, providing gains in strength development and motor skills with an acceleration in the physical recovery stage. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Effect of muscle strength training in children and adolescents with spastic cerebral palsy: A systematic review and meta-analysis

Objective: This systematic review and meta-analysis investigates the effects of strength training program in children and adolescents with cerebral palsy to improve function, activity, and participation. Data sources: Five electronic databases (MEDLINE-Pubmed, Cochrane Library, PEDro, CINAHL, and SPORTDiscus) were systematically searched for full-text articles published from inception to 30 June 2021. Review methods: Randomized controlled trials were included, who compared: (i) child population with spastic cerebral palsy population between 0 and 22 years; (ii) studies in which a muscle strength training program was performed and included dosing information; (iii) studies comparing strength training with other physical therapy technique(s) or untreated control group. Studies with similar outcomes were pooled by calculating standardized mean differences. Risk of bias was assessed with Cochrane Collaboration’s tool for assessing the risk of bias and PROSPERO’s registration number ID: CRD42020193535. Results: Twenty-seven studies, comprising 847 participants with spastic cerebral palsy. The meta-analyses demonstrated significant standardized mean differences in favor of strength training program compared to other physical therapy technique(s) or untreated control group(s) for muscle strength at the knee flexors, at the knee extensor, at the plantarflexors, maximum resistance, balance, gait speed, GMFM (global, D and E dimension) and spasticity. Conclusion: A strength training program has positive functional and activity effects on muscle strength, balance, gait speed, or gross motor function without increasing spasticity for children and adolescents with cerebral palsy in Gross Motor Function Classification System levels I, II, and III when adequate dosage and specific principles are utilized.

Meta-analysis: The Effect of Muscle Strength Training on Walking Ability of Patients with Parkinson's Disease

<i>Objective:</i> This Meta-analysis was aimed to systematically studying the effects of muscle strength training on the walking ability like balance ability, mobility ability of Parkinson's disease patients and then provide useful theoretical reference to further researches on exercise treatments on Parkinson’s disease by retrieving and collecting articles about muscle strength training. <i>Methods</i> This literature review was finally determined on searching PubMed, Elsevier, Web of science, China Journal Full-text Database (CNKI), WanFang Data and other Chinese and foreign databases and combined with manual search. The limit of the search time was from the date when the literature was recorded to 2019. A comprehensive collection of randomly controlled trials of muscle strength training on the walking ability of Parkinson's patients was done. Researchers used the Cochrance risk assessment tool to evaluate the methodological quality of the selected articles, and the ReMan 5.3.5 software to statistically process the obtained data. <i>Results</i> A total of 13 RCTs and 627 samples were included in this study. Meta-analysis of BBS balance scale show that MD=4.67 (95%CI, I²=97%, P=0.52) between muscle strength training group and non-exercise intervention group; MD=-2.67 between muscle strength training group and exercise intervention control group (95%CI, I²=7%, P<0.00001); TUGT Meta-analysis show that MD=-1.06 (95%CI, I²=75%, P=0.10) between muscle strength training group and non-exercise intervention group; MD=0.09 (95%CI, I²=0%, P=0.31) between the muscle strength training group and the control group with exercise intervention; 10MWT Meta-analysis show MD=-0.28 (95%CI), I²=98%, P<0.29) between the muscle strength training group and the control group with exercise intervention; Stride length Meta-analysis show MD=-1.85 (95%CI, I²=68%, P=0.63) between the muscle strength training group and the control group without exercise intervention; MD=-1.75 (95%CI, I²=32%, P=0.56) between the muscle strength training group and the control group with exercise intervention; MD=-1.75 (95%CI, I²=32%, P=0.56). Meta-analysis of stride speed show MD=-0.02 (95%CI, I²=0%, P=0.46) between muscle strength training group and control group without exercise intervention; MD=-0.03 (95%CI, I²=35%, P=0.52) between the muscle strength training group and control group with exercise intervention. <i>Conclusion</i> Muscle strength training can significantly improve the balance ability, mobility, and walking ability of Parkinson's disease patients, but it has no significant benefits on improving stride length and walking speed.

Effects of Muscle Strength Training on Muscle Mass Gain and Hypertrophy in Older Adults With Osteoarthritis: A Systematic Review and Meta-Analysis.

To investigate the effect of muscle strength exercise training (MSET) on lean mass (LM) gain and muscle hypertrophy in older patients with lower extremity osteoarthritis (OA). A comprehensive search of online databases was performed on April 20, 2019. Randomized controlled trials (RCTs) that reported the effects of MSET on LM, muscle thickness, and cross-sectional area (CSA) in older patients with OA were identified. A risk of bias assessment and meta-analysis were performed for the included RCTs. We included 19 RCTs with a median Physiotherapy Evidence Database score of 6 of 10 (range 3-7). In total, data from 1,195 patients (65% women, 85% with knee OA) with a mean age of 62.1 years (range 40-86 years) were analyzed. MSET resulted in significantly higher LM gain (standardized mean difference [SMD] 0.49 [95% confidence interval (95% CI) 0.28, 0.71], P < 0.00001) than did the nonexercise controls. Meta-analysis results revealed significantly positive effects of MSET on muscle thickness (SMD 0.82 [95% CI 0.20, 1.43], P = 0.009) and CSA (SMD 0.80 [95% CI 0.25, 1.35], P = 0.004) compared with nonexercise controls. No significant effects in favor of MSET were observed for any muscle outcome compared with exercise controls. Five RCTs reported nonsevere adverse events in response to MSET, whereas no RCTs reported severe events. MSET is effective in increasing LM and muscle size in older adults with OA. Clinicians should incorporate MSET into their management of patients at risk of low muscle mass to maximize health status, particularly for older individuals with OA.

The Effect of Muscle Strength Training in the Opposite Way on Increasing the Range of Motion and Working Muscles of the Ancestral Ends of Football Players

The Effect of Muscle Strength Training in the Opposite Way on Increasing the Range of Motion and Working Muscles of the Ancestral Ends of Football Players

Effects of Muscle Strength Training and Gait Training Using Integrated Volitional Control Electrical Stimulator (IVES) on Motor Paralysis and Gait Function of Mild Acute Stroke Patients: A Quasi-randomized Controlled Trial

Effects of Muscle Strength Training and Gait Training Using Integrated Volitional Control Electrical Stimulator (IVES) on Motor Paralysis and Gait Function of Mild Acute Stroke Patients: A Quasi-randomized Controlled Trial

Effect of early customized muscle strength training on postoperative rehabilitation of patients with lumbar intervertebral disc herniation

Objective To explore the effect of early customized muscle strength training on postoperative rehabilitation of patients with lumbar intervertebral disc herniation, so as to provide a basis for better promoting postoperative rehabilitation of patients. Methods From January 2017 to June 2018, 136 patients with lumbar intervertebral disc herniation admitted to Orthopaedic Department of the Second Affiliated Hospital of Harbin Medical University were selected as the study subjects. According to the admission time, they were divided into control group (63 cases) and experimental group (64 cases). Patients in the control group received routine nursing and rehabilitation after operation, while patients in the experimental group received early customized rehabilitation training for 12 weeks on the basis of routine nursing. Oswestry dysfunction score, Japanese Orthopaedic Society (JOA) score and Visual Analogue Scale (VAS) score were compared between the two groups before and after intervention. Results The Oswestry dysfunction scores of the intervention group on the 4th and 12th weeks after operation were 26.71±4.08 and 13.66 ± 3.54, lower than those of the control group (28.34±4.25 and 16.42 ± 4.13). There were significant differences between the two groups (t=2.205, 4.046, all P < 0.05 or 0.01). The JOA scores of the intervention group on the 10th day, 4th week and 12th week after operation were 19.14 ± 2.68, 23.51 ± 2.76, 25.32 ± 2.86, and those in the control group were 17.99 ± 2.51, 21.98 ± 2.64, 23.11 ± 2.72, respectively (t=2.495, 3.192, 4.461, P < 0.05 or 0.01). The VAS scores of waist and lower limbs in intervention group were 1.39 ±0.76 and 1.32 ±0.69, lower than those in the control group (1.75± 0.88, 1.61 ±0.84), respectively. The difference between the two groups was significant (t = 2.469, 2.127, P < 0.05). Conclusion Early customized muscle strength training can improve the body function and pain degree of patients with lumbar disc herniation after operation. It is simple, easy to master, easy to accept, and has good effect. It is worthy of being popularized widely in clinic. Key words: Lumbar disc herniation; Functional exercise; Rehabilitation effect; Nursing care; Muscle strength

Muscle Strength Training Alters Muscle Activation of the Lower Extremity during Side-Step Cutting in Females

The objective of this study was to examine the effects of muscle strength training on knee kinematics/kinetics and muscle activation patterns during anticipated side-step cutting. Three-dimensional knee kinematics/kinetics data and muscle activation of selected lower extremity muscles were measured while performing cutting before and after completing 10-week circuit strength training mixed typical resistance training and power training (intervention) or no training (control) from 25 female subjects. The muscle strength of quadriceps and hamstrings were measured before and after training using isokinetic dynamometer. No statistically significant differences were observed in quadriceps and hamstrings muscle strength, all kinematic/kinetic variables, and muscle activation for the control group. Both quadriceps (p = 0.005) and hamstrings (p = 0.030) muscle strength were increased after training. An increased biceps femoris (p = 0.003) and H:Q ratio of activation (p = 0.016), as well as decreased gastrocnemius muscle activation (p = 0.012) during pre-activation phase in intervention group were found. No significant differences were found in knee kinematics and kinetics both at the time frame of the initial contact and the peak tibial anterior shear force after training. In conclusion, muscle strength training altered some muscle activations of lower extremity muscles, which might affect the risk of ACL injury, but it did not change the kinematic/kinetic parameters.

Effects of muscle strength training in postmenopausal women with metabolic syndrome. Systematic review

During menopause, the risk of developing metabolic syndrome increases exponentially because of hormonal changes and old age. The aim is to perform a systematic review of randomized clinical trials to the effects of muscle strength training on the different parameters of the metabolic syndrome in postmenopausal women. A systematic review of the literature was performed in Pubmed, ScienDirect and SportDiscus using the words: Resistance training and metabolic syndrome or strength training and menopause, giving a result of 530 articles and selecting 9 of them that met the established criteria. All studies were performed in postmenopausal women, implementing muscle strength training with control group, evaluation of some component of metabolic syndrome, and with stated intensity. The studies were then evaluated using the PEDro scale. The results show that muscle strength training has been shown to have positive effects on the postmenopausal population, increasing muscle mass, improving glycemic control, regulating blood lipids, blood pressure and above all the overall metabolic syndrome score, being a safe strategy to implement in this population. According to this review, the parameters for prescribing the intensity of muscle strength exercise have not yet been determined.

Effect of Muscle Strength Training on Cognitive Functions and Depressive Symptoms for Patients with Depressive Disorder

Reseach Background. Depression nowadays is seen as a multifactorial disorder, it can occur as a function of many (combinations of) factors. Depression refers to a wide range of mental health problems characterized by the absence of a positive affect (loss of interest and enjoyment in ordinary things and experiences), persistent low mood and a range of associated emotional, cognitive, physical and behavioural symptoms (Jonge et al., 2015). Cognitive impairment is frequently observed in patients suffering from depression and is associated with poor response to treatment (Roiser et al., 2012). Physical activity and exercise can be not only an additional treatment method, but also as a primary preventive means for reducing symptoms of depression by 20–30% (Booth et al., 2012). The aim of the research was to evaluate the effect of muscle strength exercises on cognitive functions and depression symptoms for patients with depression. Methods. Ten outpatients with depression disorders were evaluated using a sociedemographic survey, Beck Depression Scale, and the Automated Neuropsychological Assessment Metrics version 4 (ANAM4) battery. Evaluation was done before and after the training sessions. The researchers performed 12 strength physical exercise sessions which lasted for 6 weeks. Results. Muscle strength exercises signifcantly reduced the expression of depressive symptoms in depressed patients. Muscle strength exercises significantly improved the cognitive function of depression patients, with the greatest influence on reaction time, attention concentration and memory. Exercises had a statistically signifcant effect on muscle strength and have had a positive effect on improving cognitive function Conclusions. The training of muscle strength can improve the cognitive function of depression and reduce depression.Keywords: depression, muscle strength exercises, cognitive functions.

Immediate effects of different treatments for the wrist joints of subdominant hands, using electromechanical reaction time.

[Purpose] The aim of this study was to examine the immediate effects of muscle strength training and neuromuscular joint facilitation distal resistance training on wrist joints by using electromechanical reaction time. [Subjects and Methods] The subjects were 12 healthy young people (24.2 ± 3.1 years, 169.7 ± 6.5 cm, 65.3 ± 12.6 kg). Two kinds of isotonic contraction techniques were applied on the wrist joint: the wrist joint extension muscle strength training and the wrist joint extension pattern of neuromuscular joint facilitation. The electromechanical reaction time, premotor time, and motor time of the left upper limb were measured before and after each intervention session of muscle strength training and neuromuscular joint facilitation. [Results] The neuromuscular joint facilitation group showed significant shortening of the electromechanical reaction time and motor time after the intervention. [Conclusion] These results suggest that the electromechanical reaction time and motor time of the wrist joint can be improved by neuromuscular joint facilitation together with proximal resistance training, which can be used as a new form of exercise for improving the functions of subdominant hand wrist joints.

Effect of muscle strength training on urinary incontinence and physical function: a randomized controlled trial in long-term care facilities

This study was done to determine whether muscle strength training programs have an impact on improving symptoms of urinary incontinence (UI) and physical function among elderly women with UI who reside in long-term care facilities. A randomized controlled trial was conducted. Participants had to be over 65 years, score over 15 score on the mini-mental state examination, and be able to walk alone or with an assistant. Seventy residents were randomly allocated to either the training group (n=35) or control group (n=35). The program consisted of 50 minutes, twice a week for 8 weeks, and included Kegel's exercise, Thera-band training and indoor walking. Main outcomes were UI symptoms, peak vaginal pressure and physical functions measured with timed up and go test (TUG), one leg standing test (OLST), activities of daily living (ADL) and grip strength. Changes in outcome measurements were calculated from baseline to 4 weeks and to 8 weeks using repeated measures ANOVA. There were significant differences in peak vaginal pressure (p<.001), TUG (p<.001), OLST (p=.012) and grip strength (p<.001) in the interaction between groups and time. Future studies are suggested to confirm the effect of muscle strength training in long-term care facilities where elderly women with UI reside.

Effects of a low-intensity dynamic-resistance training protocol using an isokinetic dynamometer on muscular strength and aerobic capacity after coronary artery bypass grafting

Study the effect of muscle strength training on muscle strength, maximal oxygen uptake (VO2max), hemodynamic and anthropometric parameters as well as quality of life after coronary artery bypass grafting (CABG). After CABG surgery, 32 patients were randomized into two groups. The first group was to perform aerobic-type training with a cycle ergometer (AT=16). The second group was to perform low-intensity muscle strength training of the quadriceps and hamstrings using an isokinetic dynamometer (i.e. 20 to 30% of peak torque) (ST=16). Before and after the strength training program we conducted a stress test, evaluation of isokinetic force production, 6-minute walking test, body impedance analysis (BIA) and SF-36 quality of life test. Compared to the AT group, the ST group showed better results with improved quadriceps strength (48.2% vs. 8.2%), VO2max (P<.001) and diastolic blood pressure at rest (P=0.01). Quality of life improved in both groups. The dynamic-resistance muscle strength training protocol using isokinetic dynamometer can safely (i.e. without clinical symptoms or changes to the ECG and arterial blood pressure) improve muscle strength and VO2max without any major risks in patients post-CABG. These findings should encourage additional studies to validate the relevance of these strength training modalities in rehabilitation centers.

Effect of Muscle Strength Training and Muscle Endurance Training on Muscle Deoxygenation Level and Endurance Performance

[Purpose] The purpose of this study was to compare the effects of muscle strength training and muscle endurance training on muscle deoxygenation level and endurance performance. [Subjects and Methods] Nineteen healthy young men were randomly assigned to a muscle strength training (STR: n = 6) group, muscle endurance training (END: n = 6) group, or a control (CON: n = 7) group. The training intensity for STR was 60°/sec × 10 repetitions × 5 sets/day and that for END was 240°/sec × 50% fatigue repetitions × 2 sets/day, 3 days/week, for 6 weeks. All subjects performed cardiopulmonary exercise testing (CPX) to measure maximum oxygen uptake, exercise time and muscle deoxygenation level of vastus lateralis, and underwent muscle strength and muscle endurance measurements pre- and post-training. [Results] In the STR group, muscle strength tended to increase, while muscle endurance significantly increased in the END group. Muscle deoxygenation level was significantly increased in both training groups. Maximum oxygen uptake did not change; however, in the END group alone, exercise time was significantly prolonged. [Conclusion] These results suggest that muscle endurance training is more effective at increasing endurance performance than muscle strength training.

Effects of Muscle Strength Training and Megestrol Acetate on Strength, Muscle Mass, and Function in Frail Older People

To determine the independent and combined effects of progressive resistance muscle strength training (PRMST) and megestrol acetate (MA) on strength, muscle mass, and function in older recuperative care patients. Double-blind, randomized, controlled intervention using a two-by-two factorial design and conducted between 1999 and 2001. University-affiliated Department of Veterans Affairs hospital. Twenty-nine patients (mean age 79.4 +/- 7.4, 90% white) aged 65 and older and had recent functional decline. After randomization to one of four treatment groups (low-resistance exercises plus 800 mg per day of MA or a placebo or high-intensity PRMST plus 800 mg/d of MA or placebo), subjects received training and the drug or placebo for 12 weeks. Change in muscle strength, mid-thigh muscle area, and aggregate functional performance score as assessed using analysis of covariance. Five subjects withdrew from the study before its completion. Based on intent-to-treat analyses, subjects who received high-intensity PRMST and placebo experienced the greatest strength gains. The addition of MA was associated with worse outcomes than with high-intensity exercise training alone, especially with regard to the leg exercises. Post hoc analysis demonstrated that subjects who received high-intensity PRMST and placebo experienced significantly greater percentage increases in leg strength than subjects in either of the MA treatment groups (P<.05 for each comparison). There was also a significant negative effect of MA on physical function. In general, subjects who received MA experienced a deterioration in aggregate physical function scores, whereas the remaining subjects improved (-0.80+/-0.40 vs 0.48+/-0.41, P=.04). There was not a significant interaction between exercise and MA for any outcome. High-intensity PRMST is a safe and well-tolerated exercise regimen for frail elderly patients. The addition of MA appears to blunt the beneficial effects of PRMST, resulting in less muscle strength and functional performance gains.

Effects of muscle strength training with whole body vibration stimulation

Effects of muscle strength training with whole body vibration stimulation

Effects of Muscle Strength Training and Testosterone in Frail Elderly Males

Determine the independent and combined effects of progressive resistance muscle strength training (PRMST) and testosterone on strength, muscle mass, and function in hypogonadal elderly male recuperative care patients. Between 1999 and 2004, 71 subjects (mean age 78.2 +/- 6.4 yr, 86% white) were enrolled. After baseline one-repetition maximum (1RM) strength testing and then randomization to one of four treatment groups (low-resistance (20% of the 1RM) exercises and weekly injections of either 100 mg of testosterone enanthate or placebo or high-intensity PRMST (> or =80% 1RM) and weekly injections), each subject received training and injections for 12 wk. Ten subjects withdrew from the study before its completion. Based on intent-to-treat analyses, strength improved in all groups, but was greater with high-intensity PRMST compared with low-resistance exercise (e.g., leg press, (mean +/- SE), 28 +/- 4 vs 13 +/- 4%, P = 0.009). Although testosterone led to significantly greater increases in midthigh cross-sectional muscle area compared with placebo (7.9 +/- 1.3 vs 2.4 +/- 1.4%, P = 0.005), it produced only a nonsignificant trend toward greater strength gains (e.g., leg press 25 +/- 4 vs 16 +/- 4%, P = 0.144). Change in aggregate functional performance score (the sum of 4 functional performance test scores) did not differ between the four intervention groups nor with high-intensity PRMST compared with low-resistance exercise (7 +/- 5 vs 15 +/- 5%, P = 0.263). There was not a significant interaction between exercise and testosterone for any outcome. High-intensity PRMST is as safe and well tolerated as a similarly structured low-resistance exercise regimen for very frail elderly patients, but produces greater muscle strength improvements. The addition of testosterone leads to greater muscle size and a trend toward greater strength but did not produce a synergistic interaction with exercise. Neither intervention had a significant effect on functional performance.

Uncertainty of knee joint muscle activity during knee joint torque exertion: the significance of controlling adjacent joint torque

In the single-joint torque exertion task, which has been widely used to control muscle activity, only the relevant joint torque is specified. However, the neglect of the neighboring joint could make the procedure unreliable, considering our previous result that even monoarticular muscle activity level is indefinite without specifying the adjacent joint torque. Here we examined the amount of hip joint torque generated with knee joint torque and its influence on the activity of the knee joint muscles. Twelve healthy subjects were requested to exert various levels of isometric knee joint torque. The knee and hip joint torques were obtained by using a custom-made device. Because no information about hip joint torque was provided to the subjects, the hip joint torque measured here was a secondary one associated with the task. The amount of hip joint torque varied among subjects, indicating that they adopted various strategies to achieve the task. In some subjects, there was a considerable internal variability in the hip joint torque. Such variability was not negligible, because the knee joint muscle activity level with respect to the knee joint torque, as quantified by surface electromyography (EMG), changed significantly when the subjects were requested to change the strategy. This change occurred in a very systematic manner: in the case of the knee extension, as the hip flexion torque was larger, the activity of mono- and biarticular knee extensors decreased and increased, respectively. These results indicate that the conventional single knee joint torque exertion has the drawback that the intersubject and/or intertrial variability is inevitable in the relative contribution among mono- and biarticular muscles because of the uncertainty of the hip joint torque. We discuss that the viewpoint that both joint torques need to be considered will bring insights into various controversial problems such as the shape of the EMG-force relationship, neural factors that help determine the effect of muscle strength training, and so on.