Effects Of Isometric Training Research Articles

Effects of isometric training and R.I.C.E. treatment on the arm muscle performance of swimmers with elbow pain.

The effects of IT and R.I.C.E. treatment on arm muscle performance in overhead athletes with elbow pain (EP) have been partially validated. However, there is a lack of research evidence regarding the efficacy of these two methods on arm muscle performance among swimmers with EP. The aim of this study was to investigate the trends and differences in the effects of IT and R.I.C.E. treatment on arm muscle performance among swimmers with EP. The main outcomes were the time effects and group effects of interventions on muscle voluntary contraction (MVC). Sixty elite freestyle swimmers from Tianjin, China, voluntarily participated in the study and completed a 10-week intervention program. Swimmers with EP in the IT group showed a positive trend in MVC, with an approximately 2% increase, whereas the MVC of subjects in the R.I.C.E. treatment group and control group decreased by approximately 4% and 5%, respectively. In comparison, the effects of the IT intervention on the MVC of the triceps and brachioradialis muscles in swimmers with EP were significant (p = 0.042 < 0.05, p = 0.027 < 0.05). The mean MVC value of the IT group (0.60) was greater than that of the other two groups (0.51, 0.50). IT has a beneficial impact on the MVC performance of the triceps and brachioradialis muscles in swimmers with EP. It is recommended that professionals consider incorporating IT into regular training routines to mitigate the risk of EP issues. Future research should examine the effectiveness of both interventions on hand-grip strength and completion time in 50-m freestyle swim drills in order for swimmers with EP to return to this sport.

Inter-hand transfer of the effects of unilateral isometric resistance training for wrist flexion and extension

Objective To investigate the effects on one hand of training the other with isometric wrist extension and flexion training and its underlying mechanism. Methods Twenty healthy young girls were recruited and randomized into a training group and a control group with 10 subjects in each, using a random number table. The subjects in the training group were accepted isometric training of the wrist extensors and flexors on the right side once every other day, 4 days a week for 6 weeks according to a pre-programmed protocol, while those in the control group had no intervention. Peak torque and surface electromyography (sEMG) were recorded and assessed before and after 6 weeks of training. Results In the training group, the average peak torque of right wrist flexion and extension were both significantly higher than before training (within-group comparison) and higher than in the control group (between-group comparison) after 6 weeks of training. The average peak torques of the left wrist in the training group in flexion and extension were (12.9±2.0) Nm and (6.4±1.3) Nm after training, both significantly higher than before the training and stronger than the control group. In the sEMG traces during wrist extension, after training the ascend velocity of the right extensor carpi ulnaris and the integrated area of the left extensor carpi ulnaris in the training group were significantly smaller than before training and in the control group. Conclusion Unilateral isometric resistance training of the wrist muscles can transfer to the contralateral side, probably by altering muscle recruitment. Key words: Contralateral recruitment; Electromyography; Maximal voluntary contraction; Muscle strength training; Wrist strength

Effects of isometric training on the knee extensor moment-angle relationship and vastus lateralis muscle architecture.

To analyse the muscle adaptations induced by two protocols of isometric training performed at different muscle lengths. Twenty-eight subjects were divided into three groups: one (K90) performed isometric training of the knee extensors at long muscle lengths (90° of knee flexion) for 8 weeks, and the second group (K50) at short muscle lengths (50°). The subjects of the third group acted as controls. Isokinetic dynamometry was utilized to analyse the net moment-angle relationship and vastus lateralis muscle thickness at three different locations, and pennation angles and fascicle length at 50 % of thigh length were measured at rest with ultrasonography. Only subjects from K90 group showed significant increases in isokinetic strength (23.5%, P < 0.001), while K50 group showed no increases in isokinetic strength: (10%, P > 0.05). There was a shift in the angle of peak torque of the K90 group to longer muscle lengths (+14.6%, P = 0.002) with greater increases in isokinetic strength, while the K50 angle shifted to shorter muscle lengths (-7.3%, P = 0.039). Both training groups showed significant increases in muscle thickness, (K90 9-14% vs. K50 5-9%) but only K90 significantly increased their pennation angles (11.7%, P = 0.038). Fascicle lengths remained unchanged. Isometric training at specific knee angles led to significant shifts of peak torque in the direction of the training muscle lengths. The greater strength gains and the architectural changes with training at long muscle lengths probably come from a combination of different factors, such as the different mechanical stresses placed upon the muscle-tendon complex.

The Effect of Isometric Training on Muscle-Tendon Unit Stiffness of Medial Gastrocnemius and the Economy of Locomotion in Highly-Trained Distance Runners

Previous studies have shown that economy of locomotion (E) is influenced by the mechanical and morphological properties of the muscle-tendon unit (MTU) of lower limbs. It has also been shown previously that these properties can be changed with isometric training (IT); however, it is not yet known if changes induced by IT result in a change in E in a group of highly-trained distance runners. PURPOSE: To determine the change in the mechanical and morphological properties of MTU of the medial gastrocnemius (MG) after 8 weeks of IT and if these changes result in a change in E in a group of highly-trained distance runners. METHODS: 6 highly-trained male distance runners (22±4yrs, 183±1cm, 72±6kg; VO2max=68±3ml·kg−1·min−1) completed an E test consisting of 5 minutes at 75, 85 and 95% of velocity corresponding to lactate threshold (vLT), both before and after 8 weeks of IT. E was measured using a metabolic cart and expressed as kcal·kg−1·km−1. IT consisted of 4×20 seconds isometric plantarflexions (PF) at 80% PFmax, 3×/wk for 8 weeks on an isokinetic dynamometer. MTU stiffness (K), thickness and pennation angle was measured using ultrasound. MTU properties and 80%max was measured every 2 weeks throughout IT. RESULTS: PFmax, K, and MTU elongation increased from baseline following IT (36±29%, p<0.10, 41±36%, p<0.10, 21±13%, p<0.10, 7±3%, p<0.08). There was no change in E at either the 75% or 85% vLT, but E at 95% vLT was improved from baseline (7±3%, p<0.08) following IT. CONCLUSIONS: 8 weeks of IT resulted in increases in PF strength and MTU stiffness of the medial gastrocnemius. Concurrently, running economy improved, but only at the highest velocity tested. Supported by NSERC Canada.

Effects of isometric training at different knee angles on the muscle–tendon complex in vivo

The purpose of this study was to investigate the influences of isometric training at different joint angles on the muscle size and function of the human muscle-tendon complex in vivo. Furthermore, we tried to gain a better understanding of the mechanisms involved in angle specificity after isometric training from the aspect of neuromuscular adaptation and the changes in the properties of the muscle-tendon complex. Nine males completed 12-week unilateral training program (70% of maximal voluntary contraction (MVC) x 15 s x six sets) on the knee extensors at 50 degrees (shorter muscle length: ST) and 100 degrees (longer muscle length: LT). The internal muscle force (mechanical stress) is higher at 100 degrees than at 50 degrees because of the difference in the moment arm length, although there were no difference in the relative torque level, contraction and relaxation times, and repetition between ST and LT. Before and after training, isometric strength at eight angles and muscle volume were determined. Tendon elongation of knee extensors was measured by ultrasonography. There was no significant difference in the rate of increment of muscle volume between the protocols. Tendon stiffness increased significantly for LT, but not for ST. Although significant gain was limited to angles at or near the training angle for ST, increases in MVC at all angles were found for LT. These results suggest that only mechanical stress (internal muscle force imposed on muscle and tendon) contributes to adaptation in the tendon stiffness, although metabolic (relative torque level, etc.) and mechanical stress relate to muscle hypertrophy. Furthermore, increment of tendon stiffness for LT might contribute to increase torque output at smaller angles other than the training angle.

Effects of isometric training on skeletal myosin heavy chain expression.

This study tested the hypothesis that an isometric resistance-training program induces upregulation of slow myosin heavy chain (MHC) expression in a fast-twitch skeletal muscle. Thus we studied the effects of two resistance-training programs on rodent medial gastrocnemius (MG) muscle that were designed to elicit repetitive isometric contractions (10-12 per set; 4 sets per session) of different duration (8 vs. 5 s) and activation frequency (100 vs. 60 Hz) per contraction during each training session (total of 6 and 12 sessions). Results showed that both training paradigms produced significant increases in muscle weight ( approximately 11-13%) after completion of training (P < 0.05). Significant transformations in MHC expression occurred and involved specifically a decrease in the relative expression of the fast type IIb MHC and concomitant increased expression of the fast type IIx MHC. These adaptations were observed in both the "white" and "red" regions of the MG, and they occurred at both the mRNA and protein levels. These adaptations were detected after only six training sessions. Neither of the training programs produced any change in the relative expression of either the slow type I MHC or the moderately fast type IIa MHC, which can be upregulated in the red MG by chronic functional overload. These findings show that the isometric protocols used in this investigation were not sufficient to induce the hypothesized changes in the myosin heavy chain isoform expression in rodent skeletal muscle.

Effect of Isometric Training on the Elbow Flexion Force Torque of Grade Five Boys

Abstract Two experiments were conducted on grade 5 boys to monitor the effects of isometric training. In the first experiment subjects were trained twice per week for 8 wk, with one group training with the elbow at 90° and the other at 60°, 90°, and 120°. In the second experiment, subjects were trained for 6 wk with the elbow at 90° only. One group trained twice per week, and the other 5 times. The training programs were all ineffective in producing a training effect, as gains in strength varied from only 0.15% to 0.75%i'wk, and no experimental group improved significantly more than its respective control group. The results of these 2 experiments are generally opposed to those previously reported, although results of at least 2 other experimental programs have suggested that young boys exhibit less positive response to isometric training than would be expected with older subjects.