Prof. J.P.N. Mishra
Mercer VS (2009) Background Step-up exercises often are suggested for strengthening the hip abductor muscles and improving balance in older adults. Little is known, however, about whether the forward or lateral version of these exercises is best for activating the hip abductor muscles. Objective The purpose of this study was to examine the electromyography (EMG) amplitude of the gluteus medius (GM) muscles bilaterally during forward and lateral step-up exercises. Design The study design involved single-occasion repeated measures. METHODS:/b> Twenty-seven community-dwelling adults (7 men and 20 women) with a mean (SD) age of 79.4 (8.0) years performed forward and lateral step-up exercises while the surface EMG activity of the GM muscles was recorded bilaterally. Pressure switches and dual force plates were used to identify the ascent and descent phases. SUBJECTS: were instructed to lead with the right lower extremity during ascent and the left lower extremity during descent. Differences in normalized root-mean-square EMG amplitudes with exercise direction (forward versus lateral) and phase (ascent versus descent) were examined by use of separate repeated-measures analyses of variance for the right and left lower extremities. The alpha level was set at.05. RESULTS: /b> Gluteus medius muscle EMG activity was significantly greater for lateral than for forward step-up exercises for the left lower extremity during the ascent phase and for both lower extremities during the descent phase. In addition, right GM muscle EMG activity was significantly greater during ascent than during descent for both exercise directions. Limitations Study limitations include use of a convenience sample and collection of limited information about participants. CONCLUSIONS:/b> Step-up exercises are effective in activating the GM muscle, with lateral step-up exercises requiring greater GM muscle activation than forward step-up exercises. Further study is needed to determine whether exercise programs for hip abductor muscle strengthening in older adults should preferentially include lateral over forward step-up exercises
Madanmohan et. al. (2008) Effect of six weeks yoga training on weight loss following step test, respiratory pressures, handgrip strength and handgrip endurance in young healthy subjects. The present study was designed to test whether yoga training of six weeks duration modulates sweating response to dynamic exercise and improves respiratory pressures, handgrip strength and handgrip endurance. Out of 46 healthy subjects (30 males and 16 females, aged 17-20 yr), 23 motivated subjects (15 male and 8 female) were given yoga training and the remaining 23 subjects served as controls. Weight loss following Harvard step test (an index of sweat loss), maximum inspiratory pressure, maximum expiratory pressure, 40 mm endurance, handgrip strength and handgrip endurance were determined before and after the six week study period.
In the yoga group, weight loss in response to Harvard step test was 64 +/- 30 g after yoga training as compared to 161 +/-133 g before the training and the difference was significant (n = 15 male subjects, P < 0.0001). In contrast, weight loss following step test was not significantly different in the control group at the end of the study period. Yoga training produced a marked increase in respiratory pressures and endurance in 40 mm Hg test in both male and female subjects (P < 0.05 for all comparisons). In conclusion, the present study demonstrates attenuation of the sweating response to step test by yoga training. Further, yoga training for a short period of six weeks can produce significant improvements in respiratory muscle strength and endurance.
Hart et. al. (2008) Yoga as steadiness training: effects on motor variability in young adults. Exercise training programs can increase strength and improve submaximal force control, but the effects of yoga as an alternative form of steadiness training are not well described. The purpose was to explore the effect of a popular type of yoga (Bikram) on strength, steadiness, and balance. Young adults performed yoga training (n = 10, 29 +/- 6 years, 24 yoga sessions in 8 weeks) or served as controls (n = 11, 26 +/- 7 years). Yoga sessions consisted of 1.5 hours of supervised, standardized postures. Measures before and after training included maximum voluntary contraction (MVC) force of the elbow flexors (EF) and knee extensors (KE), steadiness of isometric EF and KE contractions, steadiness of concentric (CON) and eccentric (ECC) KE contractions, and timed balance. The standard deviation (SD) and coefficient of variation (CV, SD/mean force) of isometric force and the SD of acceleration during CON and ECC contractions were measured.
After yoga training, MVC force increased 14% for KE (479 +/- 175 to 544 +/- 187 N, p < 0.05) and was unchanged for the EF muscles (219 +/- 85 to 230 +/- 72 N, p > 0.05). The CV of force was unchanged for EF (1.68 to 1.73%, p > 0.05) but was reduced in the KE muscles similarly for yoga and control groups (2.04 to 1.55%, p < 0.05). The variability of CON and ECC contractions was unchanged. For the yoga group, improvement in KE steadiness was correlated with pretraining steadiness (r = -0.62 to -0.84, p < 0.05); subjects with the greatest KE force fluctuations before training experienced the greatest reductions with training. Percent change in balance time for individual yoga subjects averaged +228% (19.5 +/- 14 to 34.3 +/- 18 seconds, p < 0.05), with no change in controls. For young adults, a short-term yoga program of this type can improve balance substantially, produce modest improvements in leg strength, and improve leg muscle control for less-steady subjects.
Boyle et. al. (2004) studied the effects of yoga training and a single bout of yoga on delayed onset muscle soreness in the lower extremity. The purpose of this study was to determine the effects of yoga training and a single bout of yoga on the intensity of delayed onset muscle soreness (DOMS). 24 yoga-trained (YT; n = 12) and non-yoga-trained (CON; n = 12), matched women volunteers were administered a DOMS-inducing bench-stepping exercise. Muscle soreness was assessed at baseline, 24,48,72,96, and 120 hours after bench-stepping using a Visual Analog Scale (VAS). Groups were also compared on body awareness (BA), flexibility using the sit-and-reach test (SR), and perceived exertion (RPE). Statistical significance was accepted at p
Parshad et. al. (2004) studied the role of yoga in stress management. The state of the mind and that of the body are intimately related. If the mind is relaxed, the muscles in the body will also be relaxed. Stress produces a state of physical and mental tension. Yoga, developed thousands of years ago, is recognized as a form of mind-body medicine. In yoga, physical postures and breathing exercises improve muscle strength, flexibility, blood circulation and oxygen uptake as well as hormone function. In addition, the relaxation induced by meditation helps to stabilize the autonomic nervous system with a tendency towards parasympathetic dominance. Physiological benefits which follow, help yoga practitioners become more resilient to stressful conditions and reduce a variety of important risk factors for various diseases, especially cardio-respiratory diseases.
To analyse the kinematics and electromyography characteristics of tai chi, Chan (2003) studied kinematic and electromyography analysis of the push movement in tai chi. Tai chi is a form of exercise derived from the martial art folk traditions of China. The force used in tai chi includes different principles of mechanical advantage. An experienced tai chi master was asked to perform a sequence of basic movements: ward off, roll back, press, and push. The movements were videotaped and digitised using a motion analysis system. Electromyography activities of the lumbar erector spinae, rectus femoris, medial hamstrings, and medial head of gastrocnemius were recorded by surface electrodes. The push movement data were analysed. The medial hamstrings and medial head of gastrocnemius muscle groups maintained low activity, with higher electromyography values in the lumbar erector spinae and substantially higher ones in the rectus femoris during the push movement. Both concentric and eccentric contractions occurred in muscles of the lower limbs, with eccentric contraction occurring mainly in the anti-gravity muscles such as the rectus femoris and the medial head of gastrocnemius. The forward and backward shifts in centre of gravity (CG) were mainly accomplished by increasing and decreasing respectively the joint angles of the bilateral lower limbs rather than by adopting a forward or backward postural lean. The path of the CG in the anteroposterior and mediolateral component was unique, and the sway or deviation from the path was small. The master maintained an upright posture and maintained a low CG (hips, knees and ankles bent) while travelling slowly and steadily from one position to another. The eccentric muscle contraction of the lower limbs in the push movement of tai chi may help to strengthen the muscles
Petrofsky (2001) studied the use of electromyogram biofeedback to reduce Trendelenburg gait Ten subjects suffering from incomplete spinal cord injuries, clinically diagnosed as walking with Trendelenburg gait, underwent a 2 month therapy program to strengthen their muscles and reduce their gait abnormalities. Therapy involved muscle strengthening and gait training for 2 h a day, 5 days a week in a clinic. Biofeedback was also accomplished for 30 min each training day on 'all subjects. In addition, five of the subjects wore a two-channel electromyogram (EMG) biofeedback training device at home to see if neuromuscular re-education outside of the clinical setting could speed their recovery.
The difference for these five subjects was that they would have continuous biofeedback therapy every time they walked and not biofeedback limited to only 30 min a day. Since weakness of the gluteus medius muscles is the prime contributor to Trendelenburg gait, the device provided warning tones giving feedback of improper gait through bilateral assessment of the use of the gluteus medius muscles. If too little gluteus medius activity was seen on the affected side or the step was too short in duration, the microprocessor provided an audio cue to the subjects alerting them to correct the deficit. Subjects only undergoing clinical therapy showed about a 50% reduction in hip drop due to therapy. However, the group that used the home training device showed almost normal gait after the 2 month period.
Matsumoto et. al. (2001) Progressive muscle relaxation, breathing exercises, and ABC relaxation theory This study compared the psychological effects of Progressive Muscle Relaxation (PMR) and breathing exercises. Forty-two students were divided randomly into two groups and taught PMR or breathing exercises. Both groups practiced for five weeks and were given the Smith Relaxation States Inventory before and after each session. As hypothesized, PMR practitioners displayed greater increments in relaxation states (R-States) Physical Relaxation and Disengagement, while breathing practitioners displayed higher levels of R-State Strength and Awareness. Slight differences emerged at Weeks 1 and 2; major differences emerged at Weeks 4 and 5. A delayed and potentially reinforcing aftereffect emerged for PMR only after five weeks of training-increased levels of Mental Quiet and Joy. Clinical and theoretical implications are discussed.
Raghuraj et al (1997) stated that pranayama increases grip strength without lateralized effects The present study was conducted to determine whether breathing through a particular nostril has a lateralized effect on handgrip strength. 130 right hand dominant, school children between 11 and 18 yrs of age were randomly assigned to 5 groups. Each group had a specific yoga practice in addition to the regular program for a 10-day yoga camp. The practices were: (1) right-, (2) left-, (3) alternate-nostril breathing (4), breath awareness and (5) practice of mudras. Handgrip strength of both hands was assessed initially and at the end of 10 days for all 5 groups. The right-, left- and alternate-nostril breathing groups had a significant increase in grip strength of both hands, ranging from 4 1% to 6.5%, at the end of the camp though without any lateralization effect. The breath awareness and mudra groups showed no change. Hence the present results suggest that yoga breathing through a particular nostril, or through alternate nostrils increases handgrip strength of both hands without lateralization.
Raghuraj et. al. (1997) conducted a study to compare critical flicker fusion frequency (CFF), degree of optical illusion ("di"), dexterity scores, and grip strength in three groups of subjects, viz community home girls who had learned yoga for 6 months (CHY), age-matched community home girls who had physical activity training for 6 months (CHP), and girls who were attending a regular school (SCH). There were equal numbers in each group for each of the 4 assessment (range 11 to 30 subjects) and age range was 12 to 16 years of age. The CHP group had significantly lower CFF and "di" was significantly higher (one factor ANOVA, t test for unpaired data) in the CHP group, both compared to CHY and SCH groups. Right hand grip strength was also significantly less in the CHP group compared to SCH. The results were explained by previous reports of high levels of anxiety and aggression in community-home groups, which is known to influence the four parameters described here. The better performance of the CHY group compared to CHP, suggested that yoga practice has a beneficial effect in these subjects.
Madanmohan et. al. (1992) studied the effects of yoga training on reaction time, respiratory endurance and muscle strength. There is evidence that the practice of yoga improves physical and mental performance. The present investigation was undertaken to study the effect of yoga training on visual and auditory reaction times (RTs), maximum expiratory pressure (MEP), maximum inspiratory pressure (MIP), 40 mmHg test, breath holding time after expiration (BHTexp), breath holding time after inspiration (BHTinsp), and hand grip strength (HGS). Twenty seven student volunteers were given yoga training for 12 weeks. There was a significant (P < 0.001) decrease in visual RT (from 270.0 +/- 6.20 (SE) to 224.81 +/- 5.76 ms) as well as auditory RT (from 194.18 +/-6.00 to 157.33 +/- 4.85 ms). MEP increased from 92.61 +/- 9.04 to 126.46 +/- 10.75 mmHg, while MIP increased from 72.23 +/- 6.45 to 90.92 +/- 6.03 mmHg, both these changes being statistically significant (P < 0.05). 40 mmHg test and HGS increased significantly (P < 0.001) from 36.57 +/-2.04 to 53.36 +/- 3.95 s and 13.78 +/- 0.58 to 16.67 +/- 0.49 kg respectively. BHTexp increased from 32.15 +/- 1.41 to 44.53 +/- 3.78s (P < 0.01) and BHTinsp increased from 63.69 +/- 5.38 to 89.07 +/ - 9.61 s (P < 0.05). Our results show that yoga practice for 12 weeks results in significant reduction in visual and auditory RTs and significant increase in respiratory pressures, breath holding times and HGS.
Balasubramanian et. al. (1991). Aerobic Power (V02 max) and anaerobic power were estimated in medical students before and after six weeks of yogic training. A significant increase in aerobic power and a significant decrease in anaerobic power was observed. This may be due to conversion of some of the Fast Twitch (F.T.) muscle fibres into Slow Twitch fibres (S.T.) during yogic training.
Dhume RR (1991) conducted a comparative study of the driving effects of dextroamphetamine and yogic meditation on muscle control for the performance of balance on balance board, the work is aimed to compare the relative strength of dextroamphetamine and yogic meditation on the performance of 3 different groups of medical students to concentrate on the task to balance on a balance board. Group A subjects were mediators, group B subjects were given orally 5 and 10 mg of dextroamphetamine in a capsule, 1 hr prior to the test. Group C subjects were given same capsule but with lactose in place of the drug (placebo). This last groups served as control for the study. The balance index calculated taking into account their balance time and error score at each trial of 5 min duration showed that the performance of the group B (drug) had declined with overall percentile fall of 40.6% as compared to the performance of the controls (placebo) whereas, the performance of Group A (meditators) went on steadily and progressively increasing throughout the period of 10 trial days with overall percentile rise of 27.8%. The results were conclusive to confirm earlier reports that amphetamine is not of use for improvement of task rather, it deteriorates the task performance. Contrary to that, yogic meditation is of merit to achieve concentration for mental as well as physical task.
Narayan R (1990) scientifically investigated quantitative evaluation of muscle relaxation induced by Kundalini yoga with the help of EMG integrator. The present work is aimed to quantify the degree of relaxation of muscle under the effects of Kundalini Yoga with the help of EMG integrator. The data collected from 8 individuals (4 males 4 females) on the degree of muscle relaxation at the end of meditation revealed a significantly decreased muscle activity amounting to 58% of the basal level in both the sexes.
Braud LW (1978) studied the effects of frontal EMG biofeedback and progressive relaxation upon hyperactivity and its behavioral concomitants Hyperactive children (N = 15) and no hyperactive children (N = 15) were compared. Hyperactive children were found to possess significantly higher (p less than.002) muscular tension levels and, in addition, presented more behavioral problems and had lower test scores. Both electromyography (EMG) biofeedback and progressive relaxation exercises were successful in the significant reduction of muscular tension, hyperactivity, distractibility, irritability, impulsivity, explosiveness, aggressively, and emotionality in hyperactive children. The greatest improvement was seen in the area of "emotionality-aggression" (irritability, explosiveness, impulsivity, low frustration tolerance, aggression). No differences were seen in the EMG improvement of drug and nondrug hyperactive children; both made progress under these self-control techniques. However, nondrug children made greater improvements in the behavioral area. Both EMG biofeedback and progressive relaxation resulted in improvements on the test scores of hyperactive subjects (Bender-Gestalt, Visual Sequential Memory, Digit Span, and Coding). The therapy would appear to be improved by the inclusion of mental relaxation, concentration, meditation, and mind-blanking exercises for mental control.
