Isotonic Resistance Training Research Articles

Comparison of the effects of isokinetic and isotonic strength training in team sport athletes: A randomized controlled trial

Athletes may benefit from isokinetic training (IK) to improve strength and jump performance. Previous studies comparing IK methods to isotonic resistance training (IT) have utilized high-repetition protocols and a Dynamometer, which are usually reserved for laboratory or rehabilitation settings.This study compared effects of IK and IT using ≤ 6 repetitions on strength and jump performance in 50 male, team-sport athletes (ages 18–35) during COVID-19 lockdown using the commercially-available TechnoGym BioCircuit Dynamometer. This 4-group randomized parallel study assessed the effects of an 8-week isokinetic at 80°/s (IK80; n = 16) and 25°/s (IK25; n = 12) or isotonic training program (IT; n = 15) compared to a control group (CG; n = 7) on anthropometric measurements, peak torque at 80°/s (PT80) and 25°/s (PT25), one-repetition maximum (1-RM) leg extension, and countermovement (CMJ) and squat jump height (SJ).Anthropomorphic data showed minimal differences between groups post-intervention. Strength increased in IT, and IK25 compared to CG, with no difference between intervention groups. SJ increased in all groups compared to the control group, with differences between groups. Counter movement jump (CMJ) improved only in IT and IK80 with no between-group difference.These results do support the hypothesis that low-repetition IK and IT can be used to effectively improve strength and jump performance in athletic populations. However, the efficacy of IK on CMJ depends on training velocity and repetition range, with a higher velocity training protocol (80°/s) being more effective for jump performance and lower speeds potentially more useful for improving maximal strength (25°/s).

Resistance Training in Cardiovascular Diseases: A Review on Its Effectiveness in Controlling Risk Factors.

Cardiovascular Disease (CVD), a term encompassing various disorders affecting the heart and blood vessels, includes coronary artery disease (CAD). CAD is primarily due to the development of atherosclerotic plaques that disrupt blood flow, oxygenation, and nutrient delivery to the myocardium. Risk factors contributing to CAD progression include smoking, hypertension, diabetes mellitus (DM), dyslipidaemia, and obesity. While aerobic exercise (AE) has shown promising results in controlling CVD risk factors, the impact of resistance training (RT) has not been extensively investigated. This review aims to describe the effects of RT on CVD risk factors based on studies retrieved from PubMed and Google Scholar databases. Both isometric and isotonic RT have been found to decrease systolic blood pressure (SBP), diastolic blood pressure, or mean arterial pressure, with SBP showing a more significant reduction. Hypertensive patients engaging in RT alongside a calorie-restricted diet demonstrated significant improvements in blood pressure. RT is associated with increased nitric oxide bioavailability, sympathetic modulation, and enhanced endothelial function. In type-2 DM patients, 8-12 weeks of RT led to improvements in fasting blood glucose levels, insulin secretion, metabolic syndrome risk, and glucose transporter numbers. Combining AE with RT had a more significant impact in reducing insulin resistance and enhancing blood glucose compared to performing exercises separately. It also significantly decreased total cholesterol, triglycerides, and low-density lipoprotein levels while increasing high-density lipoprotein within 12 weeks of application. However, improvements are considered insignificant when lipid levels are already low to normal at baseline. The administration of RT resulted in weight loss and improved body mass index, with more pronounced effects seen when combining AE with RT and a calorie-restricted diet. Considering these results, the administration of RT, either alone or in combination with AE, proves beneficial in rehabilitating CAD patients by improving various risk factors.

Effects of Isometric and Isotonic Training on Health-Related Fitness Components in Young Adults

Isometric and isotonic exercises are important modes of resistance training for enhancement of athletic performance. However, less is known about their effects on fitness and health in recreationally physically active individuals. This study evaluates the effect of isometric and isotonic training protocols on health-related fitness components in young university students. A group of one hundred males (18–24 years) underwent a 12-week isotonic and isometric training program (two days per week, 45 min per session). They were randomized into two groups, group A (n = 50) and group B (n = 50). While group A underwent the isotonic resistance training, the group B completed isometric resistance training. Prior to and after training programs, body mass index (BMI) was measured and the bench press 1RM test, sit-ups test, sit and reach test, and 12 min run/walk test were performed. Results showed significant improvements in BMI, bench press 1RM test, sit-ups test, sit and reach test, and 12 min run/walk test after both isotonic and isometric training protocols. The isotonic training group increased in BMI by 2.70%, bench press 1RM by 34.45%, number of sit-ups by 24.13%, sit and reach distance by 29.12%, and 12 min run/walk distance by 19.82%. Isometric training group increased in BMI by 1.96%, bench press 1RM by 14.23%, number of sit-ups by 7.80%, sit and reach distance by 6.92%, and 12 min run/walk distance by 6.99%. A comparison of these training protocols revealed that the isotonic group improved significantly more than the isometric group in the bench press 1RM (20.22%), number of sit-ups (16.33%), and sit and reach distance (22.2%) but not in the 12 min run/walk distance (12.83%) and BMI (0.74%). These findings indicate that both isotonic and isometric resistance training protocols improve health-related fitness components in young adults; however isotonic training is more efficient than isometric training in increasing their muscle strength, muscular endurance, and flexibility.

The Influence Of Normalization Technique On Between-muscle Activation During A Back-squat: Methodological Considerations

BACKGROUND/OBJECTIVE: Currently, no gold standard electromyography (EMG) normalizing technique exists when conducting between-muscle comparisons of muscle activity during isotonic resistance training exercises. The aim of this study was to assess if between-muscle activation during the back-squat differed among electromyography (EMG) normalization techniques when normalizing to: (1) 1 repetition maximum (1RM), (2) maximal voluntary isometric contraction (MVIC), and (3) the first of a set of three repetitions (Rep1%) in trained female lifters. METHODS: Thirteen participants completed a back-squat 1RM, MVIC of the rectus-femoris (RF) and gluteus-maximus (GM), and three repetitions of the back-squat at 80% 1RM. For the 1RM and MVIC normalization techniques, the average of the peak RMS signal of both muscles during the three submaximal reps were normalized to the peak 1RM and MVIC signals. The Rep1% averaged the peak RMS signals of both muscles during the 2nd and 3rd submaximal repetitions normalized to the peak signal during the 1st repetition. RESULTS: The RF-GM between-muscle EMG (ΔEMG) differed among normalization techniques (p < 0.001, ηp2 = 0.48). Post-hoc pairwise comparisons indicated MVIC normalization elicited different ΔEMG with large effects compared to both 1RM (p = 0.037; d = 1.2) and Rep1% (p = 0.004; d = 1.9) techniques, but the 1RM and Rep1% did not produce different ΔEMG (p = 0.27; d = 0.8). CONCLUSION: Our findings suggest EMG normalization technique influences the magnitude and direction of between-muscle activation during common lifting exercises, and we recommend normalizing isotonic movements to dynamic normalization methods such as a 1RM or Rep1%. Key Words: Electromyography; Methodology; Signal processing; Lower extremity; Training; Exercise

Mobility Outcomes From Resistance Training Delivered via Flash Drive to Overweight/obese Patients In A Clinical Setting

Elastic and isotonic resistance training can improve health and fitness. Little is known about the impact of a home-based, structured program delivered via flash drive videos to weight management patients in a clinical setting. PURPOSE: To measure functional fitness/mobility after 12 weeks of a home-based, video led resistance-training program (Mini BIRST) designed as short interval workouts using dumbbells or Theraband CLX elastic resistance bands. METHOD: Overweight/obese participants (n=21, 51.5 yrs, BMI 33.2 kg•m-2) enrolled in the Health Management Resources (HMR) weight management program, self-selected to join the study and were assessed for baseline health and mobility. They were randomized into 2 groups: 3 weeks of isotonic resistance followed by 3 weeks of elastic resistance (10-20 min/day, 2-3 days/wk, 6 wks) using a cross-over design. Participants then performed full body CLX-only circuit exercises (20 min/day, 2-3 days/wk, 6 wks). Both home-based programs were delivered via written handouts and flash drive videos. Functional fitness/mobility was assessed using standardized tests. Repeated measures ANOVA were conducted and a p-value of <0.05 was used to indicate significant changes. An opinion survey was conducted to determine attitudes about the program and delivery. RESULTS: Participants exercised 3 days/wk for 12 weeks with 83% compliance. Mobility improved for chair stand (26%), arm curl (35%), aerobic endurance (25%), and flexibility in both legs (4% right, 2% left). Participants showed no changes for weight or BMI, but successfully maintained “weight neutral” during the 12-week. Participants trended toward an increase in physical activity (9%), over baseline. ” Participant opinions revealed they “Liked” the program overall” (75%), said they “Felt good” (70%), was “Convenient to do” (85%), “Liked the flash drive delivery” (85%) and would “Continue the program” (85%). CONCLUSIONS: Participants complied to and enjoyed the home-based, dumbbell and CLX resistance band short-burst workouts delivered via flash drive videos and illustrated handouts, resulting in improved mobility and aerobic endurance. Further study is needed to determine long- term impact on adherence, weight and health. Support for this study provided by Performance Health, Akron, OH.

Improvement in muscle strength with low-load isotonic training depends on fascicle length but not joint angle.

In this study we investigate whether low-load isotonic training will elicit greater improvement in muscle strength at the same fascicle length, rather than at the same joint angle. Sixteen healthy men (24.1 ± 2.5 years of age) were randomly divided into intervention and control groups. Pre- and posttraining maximum isometric and isokinetic strengths and fascicle lengths of the medial gastrocnemius muscle were measured. Isotonic resistance training at 15 ° to 30 ° ankle plantarflexion at low intensity was conducted for 4 weeks. The maximum isometric and isokinetic strength of the intervention group increased significantly only at 15 ° dorsiflexion and 8 ° to 12 ° dorsiflexion. Fascicle length during maximum voluntary contraction at 15 ° dorsiflexion to 0 ° was similar to fascicle length under training conditions. It is possible that the improvement in muscle strength with low-load training depends on fascicle length rather than joint angle. Muscle Nerve 57: 83-89, 2018.

Comparison Of Muscle Activation Using A Nitrogen Piston-based Resistance Device With Free Weights

Resistance training is especially important for populations at risk of sarcopenia and osteopenia such as older adults or astronauts working in microgravity. A limitation of common forms of resistance training is that they are gravity-based and lack efficacy in microgravity. Therefore, to maintain muscle and bone mass in microgravity, an alternative solution must be sought. One alternative is the use of a gas-filled piston-based resistance training system. PURPOSE: The goal of the current study is to assess the effectiveness of a Nitrogen-filled piston-based resistance training system (NitroForce) compared to isotonic resistance training. METHODS: Thirty recreational athletes performed five repetitions of squat and toe-raise exercises, in two experimental conditions: NitroForce and Isotonic. The NitroForce condition was characterized by resistance of approximately 70% of the participant’s one repetition maximum (1RM) while resistance was supplied using the NitroForce system. Isotonic condition was characterized by participants performing each exercise with resistance equal to 70% of 1RM provided by free weights. Surface electromyography (sEMG, 1928 Hz, Delsys) was recorded from the vastus medialis (VM), vastus lateralis (VL), and the lateral (LG) and medial heads of the gastrocnemius (MG). Mean sEMG amplitude was quantified using the RMS (20 ms smoothing window) and normalized to MVC for each muscle in each condition. Paired samples t-tests were used to compare mean sEMG values. Significance was set at p < 0.05. RESULTS: In the squat exercise, VM activation was significantly greater in the NitroForce compared to isotonic condition (p = 0.039), but no differences were observed in the VL (p = 0.367). No significant differences were observed between the NitroForce and isotonic conditions for the LG (p = 0.400) or MG (p = 0.442) in the toe-raise exercise. CONCLUSIONS: These data demonstrate that muscle activation intensity as measured by sEMG is not significantly different in the NitroForce compared to isotonic conditions. Therefore, the NitroForce provides a similar level of resistance and overload to standard isotonic resistance training loads. However, due to the non-gravity-based nature of the NitroForce, it may provide a better resistance training solution in microgravity environments.

Stabilometric response during single-leg stance after lower limb muscle fatigue

This study sought to analyze the effect of muscle fatigue induced by active isotonic resistance training at a moderate intensity by measuring the knee extension motion during the stabilometric response in a single-leg stance among healthy university students who perform resistance training on a regular basis. Eleven healthy university students were subjected to a one-repetition maximum (1RM) test. In addition, stabilometric assessment was performed before and after the intervention and consisted of a muscle fatiguing protocol, in which knee extension was selected as the fatiguing task. The Shapiro-Wilk test was used to investigate the normality of the data, and the Wilcoxon test was used to compare the stabilometric parameters before and after induction of muscle fatigue, at a significance level of p≤0.05. Descriptive statistics were used in the analysis of the volunteers' age, height, body mass, and body mass index (BMI). The sample population was 23.1±2.7 years of age, averaged 1.79.2±0.07 m in height and 75.6±8.0 Kg in weight, and had a BMI of 23.27±3.71 Kg.m-2. The volunteers performed exercises 3.36±1.12 days/week and achieved a load of 124.54±22.07 Kg on 1RM and 74.72±13.24 Kg on 60% 1RM. The center of pressure (CoP) oscillation on the mediolateral plane before and after fatigue induction was 2.89±0.89 mm and 4.09±0.59 mm, respectively, while the corresponding values on the anteroposterior plane were 2.5±2.2 mm and 4.09±2.26 mm, respectively. The CoP oscillation amplitude on the anteroposterior and mediolateral planes exhibited a significant difference before and after fatigue induction (p=0.04 and p=0.05, respectively). The present study showed that muscle fatigue affects postural control, particularly with the mediolateral and anteroposterior CoP excursion.

Study on cross education of six-week unilateral isotonic resistance training for wrist flexion and extension

Study on cross education of six-week unilateral isotonic resistance training for wrist flexion and extension

Clinical Outcomes of Isotonic Resistance Training for a Female with Stable Chronic Heart Failure

Clinical Outcomes of Isotonic Resistance Training for a Female with Stable Chronic Heart Failure

Efeito do treinamento contra-resistência isotônico com duas velocidades de movimento sobre os ganhos de força

Considerando a necessidade de prescrever o treinamento adequadamente, o objetivo deste estudo foi comparar o efeito do treinamento contra-resistência, isotônico, a 0,44 e 1,75 rad·s¹ sobre os ganhos de força muscular. Quatorze voluntários saudáveis foram estratificados em grupos lento (GL: 0,44 rad·s¹; n = 8; 26 ± 7 anos; 66 ± 12 kg) e rápido (GR: 1,75 rad·s¹; n = 6; 28 ± 7 anos; 55 ± 9 kg) exercitando agachamento e supino reto (1 série, 8-10 RM, 3 x/semana, 12 semanas). Seis desses sujeitos fizeram parte de um grupo de comparação (GC: 25 ± 6 anos; 59 ± 13 kg) e não treinaram durante um período de controle de 12 semanas antecedendo o treinamento. O teste t dependente não mostrou diferenças nas variáveis medidas para GC. A ANOVA 2 x 2 com medidas repetidas mostrou ganhos significativos (P &lt; 0,05) em ambos os grupos de treinamento e ambos os exercícios para 1 RM (GL: 27,6 ± 16,8% e 16,8 ± 11,8%; GR: 21,4 ± 12,6% e 16,2 ± 14,1%, agachamento e supino, respectivamente) e 8-10 RM testado a 0,44 rad·s¹ (GL: 36,0 ± 22,4% e 14,7 ± 9,2%; GR: 31,1 ± 19,2% e 18,8 ± 8,7%) e 1,75 rad·s¹ (GL: 27,2 ± 11,1% e 15,2 ± 11,4%; GR: 23,6 ± 19,2% e 20,9 ± 9,8%), sem diferenças significativas entre grupos. Resultados deste estudo não deram suporte à especificidade da velocidade no treinamento com equipamento isotônico.

Does Nutritional Supplementation Influence Adaptability of Muscle to Resistance Training in Men Aged 48 to 72 Years

Isotonic strength training can result in neuromuscular improvements evidenced in other forms of muscular effort, ie, isokinetic or isometric, especially in young subjects; however, it is unclear if older muscle maintains this same adaptive ability. Additionally, it is not known if the benefits of resistance training can be augmented by creatine and protein supplementation in older men. Therefore, the purpose of this study was to assess changes in isokinetic parameters at varying speeds in men aged 48 to 72 years (mean=57+/-2.1) following 16 weeks of isotonic resistance training and creatine and/or protein supplementation. Forty-two male subjects were randomly assigned to 1 of 4 training groups: (1) resistance training placebo (n=10), (2) resistance trained creatine supplemented (n=10), (3) resistance trained protein supplemented (n=11), and (4) resistance trained creatine and protein supplemented (n=11). The program consisted of progressive overload resistance training (3 d/wk) and supplement consumption following the workout. There were significant time effects (P>.05) for peak torque (PT), time to PT, and average power for both the knee extensors and flexors at all velocities. However, no significant group or group by time interactions were noted, indicating that the supplementation protocols had no added benefits. Men aged 48 to 72 years maintained their ability to improve isokinetic muscle function following isotonic training, however, supplementation did not enhance muscle adaptability.