Isokinetic Arm Research Articles

Prior heat exposure diminishes upper-body endurance work capacity and maximal arm and leg strength in young men.

Workers often experience heat exposure before manual labour. This study investigated whether prior heat exposure diminished upper-body endurance work capacity and maximal isokinetic arm and leg strength in young men. Ten male participants completed two trials in a climatic chamber maintained at 25°C with 50% relative humidity. The two trials required them to complete a 30-min pre-exercise water-immersion at either 40°C (HOT) to provoke an approximately 1°C rise in rectal temperature (Tre) or 36°C (CON) to maintain a normal Tre. Pre- and post-immersion and following arm-cranking, isokinetic maximal voluntary contraction (MVC) torque was assessed for the elbow flexors and knee extensors. During arm-cranking, time to exhaustion was measured using arm crank ergometry at 60% peak oxygen uptake. Electromyography was recorded from the elbow flexors and knee extensors to calculate the integrated electromyography. Tre at post-immersion was higher in HOT (Mean ± SD, 38.1 ± 0.3°C) than CON (37.1 ± 0.3°C; P < 0.01). Time to exhaustion was less in HOT (41 ± 13min) than CON (52 ± 12min; P < 0.01). Isokinetic MVC torque in the elbow flexors and knee extensors was lower in HOT than CON (both P < 0.05). The integrated electromyography of the elbow flexors and knee extensors were lower in HOT than CON (both P < 0.05). This study indicates that a 1°C rise in Tre by prior heat exposure reduces time to exhaustion during arm-cranking and isokinetic MVC torque of the elbow flexors and knee extensors. Workers should be careful about reductions in upper-body endurance work capacity and maximal arm and leg strength when exposed to heat before manual labour.

WOMEN’S SWIMMING – SELECTED METHODS FOR OPTIMISING COMPETITIVE TRAINING

This article presents selected results of the authors' research into the topic of strength ability of female competitive swimmers with the aim of optimising training to achieve the best possible results. Apart from a review of the literature on sports swimming, muscle strength analysis and the specificity of strength training in sports swimming, characteristic movements of the upper limbs observed during sports swimming are discussed and the results of previous research concerning the measurement of strength in female competitive swimmers are presented. The study group consisted of 12 female swimmers. Measurements were carried out twice. The first measurement took place in January 2014. After completing this series of measurements, the necessary changes were proposed. Measurement two took place in January 2015. Additionally, they had to be at least 14 years old. The subjects were included in the dietary catering. A high-protein and high-carbohydrate diet was used, tailored to the needs of each female athlete. The daily routine and lifestyle of the subjects consisted of two workouts (morning and afternoon). The lifestyle of the subjects and their nutrition can be considered comparable. To this end, laboratory measurements of biomechanical muscle properties were used, and land tests (static and dynamic), tethered swimming tests and isokinetic tests using state-of-the-art dynamometers were also conducted. The isokinetic arm measurement method should be used for the ongoing and periodic monitoring of female high level competitive swimmers. A specific annual strength training intervention is not sufficient to induce positive changes in arm muscle strength parameters in female competitive swimmers. General development, targeted and specific strength training of the arm muscles as well as compensatory and compensatory programmes tailored to the individual needs of high level competitive swimmers should be planned and applied to consistently eliminate possible deficiencies in strength parameters. Changes in some strength parameters of arm muscles over a yearly cycle had a positive effect on sports performance. Long-term, individualised programmes of improvement of specific strength parameters of arm muscles should be conducted to improve the performance of high-level sports swimmers.

A Dataset of Human Motion and Muscular Activities in Manual Material Handling Tasks for Biomechanical and Ergonomic Analyses

Manual Material Handling (MMH) activities represent a large portion of the workers’ tasks in the tertiary sector. The ability to monitor, model, and predict human behaviours are crucial to both the design of productive human-robot collaboration and an efficient physical exposure assessment system that can prevent Work-related Musculoskeletal Disorders (WMSDs), with the ultimate goal of improving workers’ quality of life. The combined use of wearable sensors and machine learning (ML) techniques can fulfil these purposes. Inertial Measurement Units (IMUs) and surface Electromyography (sEMG) allow collecting kinematic data and muscular activity information that can be used for biomechanical analyses, ergonomic risk assessment, and as input of ML algorithms aimed at joint torque/load estimation, and Human Activity Recognition (HAR). The latter needs a large amount of annotated training samples, and the use of publicly available datasets is the way forward. Nowadays, the majority of them concern Activities of Daily Life (ADLs) and, including only kinematic data, have limited applications. This paper presents a fully labelled dataset of working activities that include full-body kinematics from 17 IMUs and upper limbs sEMG data from 16 channels. Fourteen subjects participated in the experiment performed in laboratory settings for overall 18.6 hours of recordings. The activities are divided into two sets. The first includes lifting, lowering, and carrying objects, MMH activities suitable for ergonomic risk assessment, and HAR. The second includes isokinetic arm movements, mainly targeting load and joint torque estimation.

Effects of 7-week Resistance Training on Handcycle Performance in Able-bodied Males.

The effect of an upper body resistance training program on maximal and submaximal handcycling performance in able-bodied males was explored. Eighteen able-bodied men were randomly assigned to a training group (TG: n=10) and a control group (CG: n=8). TG received 7 weeks of upper body resistance training (60% of 1 repetition maximum (1RM), 3×10 repetitions, 6 exercise stations, 2 times per week). CG received no training. Peak values for oxygen uptake (V˙O2peak), power output (POpeak), heart rate (HRpeak), minute ventilation (V˙OEpeak) and respiratory exchange ratio (RERpeak), submaximal values (HR, V˙O2, RER, PO, and gross mechanical efficiency (GE)), and time to exhaustion (TTE) were determined in an incremental test pre- and post-training. Maximal isokinetic arm strength and 1RM tests were conducted. Ratings of perceived exertion (RPE) were assessed. A two-way repeated measures ANOVA and post-hoc comparisons were performed to examine the effect of time, group and its interaction (p<0.05). TG improved on POpeak (8.55%), TTE (10.73%), and 1RM (12.28-38.98%). RPE at the same stage during pre- and post-test was lower during the post-test (8.17%). Despite no improvements in V˙O2peak, training improved POpeak, muscular strength, and TTE. Upper body resistance training has the potential to improve handcycling performance.

Examination of lower-upper limb of power and force parameters of elite athletes

Background and Study Aim. In this study, it is aimed to evaluate the power and force parameters of lower and upper extremities of the individual and team athletes who practice different branches.&#x0D; Material and Methods. 32 elite athletes, most of whom are university students, with an average age of 21.16 ± 2.08, who are active in sports, participated in the study. The groups were formed from Boxing and Handball (BG and HG) branches in which the upper extremities are used predominantly and from Taekwondo and Football (TG and FG) branches in which the lower extremities are used predominantly. The anaerobic power values of each individual’s upper and lower extremities were measured by a Monark 894E. The isokinetic force values of dominant arms and legs were measured by a Cybex humac norm device.&#x0D; Results. After examination of the data it was found that the upper extremity power values of BG and HG were significantly higher than TG when the top values of peak powers (PP) were evaluated. In the evaluations with respect to leg 60°/s and 180°/s extension and flexion; HG and FG was significantly higher than TG in 60°/s extension at PP; HG and FG were significantly indifferent but they were significantly higher than BG and TG in 60°/s flexion at PP. In the comparisons of the groups’ 60°/s and 180°/s extension and flexion values of lower extremities anaerobic power and isokinetic force and lower extremities’ wingate values, a number of positive relations were found between all of the groups. All of the groups were positively related to each other in terms of upper extremities wingate and 60°/s, 180°/s internal and external isokinetic forces. &#x0D; Conclusions. Both the isokinetic arm force values and arm wingate levels were higher in the branches in which the upper extremities are used predominantly than the branches in which the lower extremities are used predominantly. On the other hand, the difference seen in the upper extremities was not seen in the lower extremities.

The efficacy of rooibos Aspalathus linearis as an ergogenic aid during exercise

This study investigated whether rooibos herbal tea Aspalathus linearis has an ergogenic effect during a fatiguing arm strength test to exhaustion. Thirty-two male participants were randomised in a single blinded, cross-over placebo controlled study in which they ingested standardised rooibos or placebo capsules for four weeks prior to a fatiguing elbow flexion/extension exercise test entailing five sets/bouts of 15 repetitions of maximum voluntary contractions separated by 10-second rest intervals on a Biodex System 3 at a speed of 60° per second. Peak torque flexion (Nm) was consistently higher in the rooibos experimental (Re) compared to the placebo control (Pc) across the five exercise bouts, and this performance trend during flexion was also seen in the total work (joules) completed, although not significant (P > 0.05). It appears that the antioxidant properties of rooibos, may have contributed to an improvement in physical performance during a maximal isokinetic arm exercise protocol to induce fatigue.

The efficacy of rooibos Aspalathus linearis as an ergogenic aid during exercise

This study investigated whether rooibos herbal tea Aspalathus linearis has an ergogenic effect during a fatiguing arm strength test to exhaustion. Thirty-two male participants were randomised in a single blinded, cross-over placebo controlled study in which they ingested standardised rooibos or placebo capsules for four weeks prior to a fatiguing elbow flexion/extension exercise test entailing five sets/bouts of 15 repetitions of maximum voluntary contractions separated by 10-second rest intervals on a Biodex System 3 at a speed of 60° per second. Peak torque flexion (Nm) was consistently higher in the rooibos experimental (Re) compared to the placebo control (Pc) across the five exercise bouts, and this performance trend during flexion was also seen in the total work (joules) completed, although not significant (P > 0.05). It appears that the antioxidant properties of rooibos, may have contributed to an improvement in physical performance during a maximal isokinetic arm exercise protocol to induce fatigue.

Test-Retest Reliability of Isokinetic Arm Strength Measurements in Competitive Swimmers.

Swimming motor patterns lead internal rotators to grow stronger than antagonist muscles, what may increase the risk of injury in swimmers. Injury prevention often involves the improvement of external rotators strength, as well as the external rotation/internal rotation ratio. The current research aimed to evaluate the test-retest reliability of shoulder concentric rotation strength in competitive swimmers using an isokinetic dynamometer. The study enrolled 35 competitive swimmers aged between 13 and 19 years. Concentric movements were performed including internal and external rotations of the shoulder joint following the instructions of the standardized protocol. The angular velocity of the test was defined at 60º/s. Outcome measures were peak torque (Nm) and work (J), measured in both, the dominant and non-dominant arms. The external rotation/internal rotation ratio was also calculated. Reliability was excellent for peak torque and work. For the external rotation/internal rotation ratio, the ICC oscillated between 0.744 and 0.860 for the work ratio of the non-dominant arm and the peak torque ratio of the dominant arm, respectively. In general terms, better reliability was observed for peak torque compared with work, for external rotation compared with internal rotation, and for the dominant arm compared with the non-dominant one.

Physiology of Distinct Modes of Muscular Contraction

Physiological changes in musculature allow widespread movements in human body. Correspondingly, varying in muscle prototypes characterise direct different training paradigms in therapeutics practice or can governs athletic performances. Mode of muscle contraction type are isometric, concentric or eccentric. Great examples of concentric exercise are walking- up-hill, stair ascent and lifting a dumbbell in bicep curl or pushing a bar up. Examples of eccentric muscle actions are walking - down-hill, satire decent and, isokinetic arm and leg extensions. During isometric muscle contraction the length of muscle does not change while muscle exert force .This type of movement can be seen while a person performs a maximal voluntary contractions (MVCs).Eccentric exercises increasing the concentric and isometric contraction as well. Performing the eccentric muscle contraction in daily life enhance quality of life and lifespan due to increasing muscle strength with low cost of energy consuming and thus it can apply in variety of domains. A simple walking task such as downhill - walking (i.e. 30 min) can provide the aforementioned conditions.

Gas exchange kinetics following concentric-eccentric isokinetic arm and leg exercise

PurposeTo evaluate the effects of exercise velocity (60, 150, 240deg∙s−1) and muscle mass (arm vs leg) on changes in gas exchange and arterio-venous oxygen content difference (avDO2) following high-intensity concentric-eccentric isokinetic exercise. MethodsFourteen subjects (26.9±3.1years) performed a 3×20-repetition isokinetic exercise protocol. Recovery beat-to-beat cardiac output (CO) and breath-by-breath gas exchange were recorded to determine post-exercise half-time (t1/2) for oxygen uptake (V˙O2pulm), carbon dioxide output (V˙CO2pulm), and ventilation (V˙E). ResultsSignificant differences of the t1/2 values were identified between 60 and 150deg∙s−1. Significant differences in the t1/2 values were observed between V˙O2pulm and V˙CO2pulm and between V˙CO2pulm and V˙E. The time to attain the first avDO2-peak showed significant differences between arm and leg exercise. ConclusionsThe present study illustrates, that V˙O2pulm kinetics are distorted due to non-linear CO dynamics. Therefore, it has to be taken into account, that V˙O2pulm may not be a valuable surrogate for muscular oxygen uptake kinetics in the recovery phases.

Grip strength is a representative measure of muscle weakness in the upper extremity after stroke

Background: Muscle weakness is the most common impairment in the upper extremity after stroke, leading to a reduced ability to use the arm and the hand in daily activities. Grip strength is easier to measure than precise, but more time-consuming, isokinetic and isometric arm muscle strength measurements. It would therefore be advantageous in a clinical setting if grip strength could be used as a proxy for muscle strength in the entire upper extremity.Objective: To investigate the association between grip strength and isometric and isokinetic arm muscle strength in persons with chronic stroke.Methods: Forty-five persons with mild-to-moderate paresis in the upper extremity, at least 6 months post-stroke participated. Isometric grip strength was measured with a computerized grip dynamometer and arm strength (isometric shoulder abduction and elbow flexion as well as isokinetic elbow extension and flexion) with an isokinetic dynamometer. Pearson’s correlation coefficient was used to determine the association between the muscle strength measurements.Results: There were significant correlations (p < .0001) between grip strength and all arm strength measurements in both the more affected (r = 0.77–0.82) and the less affected upper extremity (r = 0.65–0.82).Conclusion: This cross-sectional study showed that grip strength is strongly associated with muscle strength in the arm in persons in the chronic phase after stroke. As grip strength is easy to measure and less time-consuming than arm muscle strength measurements, this implies that grip strength can be a representative measure of muscle weakness of the entire upper extremity in the chronic phase after stroke.

Intra-rater Reliability of Arm and Hand Muscle Strength Measurements in Persons With Late Effects of Polio

BackgroundMuscle weakness in the upper limb is common in persons with late effects of polio. To be able to measure muscle strength and follow changes over time, reliable measurements are needed. ObjectiveTo evaluate the intra-rater reliability of isometric and isokinetic arm and hand muscle strength measurements in persons with late effects of polio. DesignA test-retest design. SettingsA university hospital outpatient clinic. ParticipantsTwenty-eight persons (mean age 68 years, SD 11 years) with late effects of polio in their upper limbs. MethodsIsometric shoulder abduction, isokinetic concentric elbow flexion and extension, isometric elbow flexion, and isometric grip strength were measured twice, 14 days apart. Reliability was evaluated with the intra-class correlation coefficient, the mean difference between the test sessions (d¯), together with the 95% confidence intervals for d¯ , the standard error of measurement (SEM and SEM%), the smallest real difference (SRD and SRD%), and Bland-Altman graphs. Main Outcome MeasurementsA fixed dynamometer (Biodex) was used to measure arm strength and an electronic dynamometer (GRIP-it) was used to measure grip strength. ResultsIntra-rater reliability was high, with intra-class correlation coefficients between 0.87 and 0.98. The SEM%, representing the smallest change for a group of persons, ranged from 7%-24% for all strength measurements, and the SRD%, representing the smallest change for an individual person, ranged from 20%-67%. ConclusionMuscle strength in the upper limbs can be reliably measured in persons with late effects of polio. However, the measurement errors indicate that the method is more suitable to detect changes in muscle strength for a group of persons than for an individual person.

Isometric and isokinetic muscle strength in the upper extremity can be reliably measured in persons with chronic stroke.

To evaluate the test-retest reliability of isometric and isokinetic muscle strength measurements in the upper extremity after stroke. A test-retest design. Forty-five persons with mild to moderate paresis in the upper extremity > 6 months post-stroke. Isometric arm strength (shoulder abduction, elbow flexion), isokinetic arm strength (elbow extension/flexion) and isometric grip strength were measured with electronic dynamometers. Reliability was evaluated with intra-class correlation coefficients (ICC), changes in the mean, standard error of measurements (SEM) and smallest real differences (SRD). Reliability was high (ICCs: 0.92-0.97). The absolute and relative (%) SEM ranged from 2.7 Nm (5.6%) to 3.0 Nm (9.4%) for isometric arm strength, 2.6 Nm (7.4%) to 2.9 Nm (12.6%) for isokinetic arm strength, and 22.3 N (7.6%) to 26.4 N (9.2%) for grip strength. The absolute and relative (%) SRD ranged from 7.5 Nm (15.5%) to 8.4 Nm (26.1%) for isometric arm strength, 7.1 Nm (20.6%) to 8.0 Nm (34.8%) for isokinetic arm strength, and 61.8 N (21.0%) to 73.3 N (25.6%) for grip strength. Muscle strength in the upper extremity can be reliably measured in persons with chronic stroke. Isometric measurements yield smaller measurement errors than isokinetic measurements and might be preferred, but the choice depends on the research question.

A-44 Free Communication/Poster - Oxygen Uptake Kinetics

Many investigators utilize exhaustive high-intensity leg cycling exercise (e.g., time trial) to induce fatigue and evaluate associated changes in maximal neuromuscular function. To our knowledge, there are no reports that compare the development of fatigue and recovery of voluntary neuromuscular function to leg and arm locomotor exercise. PURPOSE: To evaluate changes in maximum cycling power (Pmax) before, during, and immediately after exhaustive high-intensity endurance 1) leg and 2) arm cycling. METHODS: Ten trained cyclists performed maximal isokinetic leg cycling trials (3 s, 90 rpm) before and again 0, 0.25, 0.75, 2.0, 3.3, 6.6, and 10 min after an isokinetic leg cycling time trial (TTleg, 10 min, 90 rpm). Four individuals who were upper body endurance trained performed maximal isokinetic arm cycling trials (3 s, 75 rpm) before and again 0, 0.25, 0.75, 2.0, 3.3, 6.6, and 10 min after an isokinetic arm cycling time trial (TTarm, 10 min, 75 rpm). Cycling power was measured with a power meter and fatigue was estimated by comparing relative exercise-induced changes in Pmax. RESULTS: Mean power produced during TTleg was greater than TTarm (360±51 vs. 157±22 W, P<0.01). Heart rate (183±8 vs. 179±17 bpm), overall RPE (19.2±0.9 vs. 18.9±0.6 scale units), limb-specific RPE (19.4±0.7 vs. 18.9±0.6 scale units), and whole-blood lactate (11.4±2.1 vs. 11.8±2.8 mmol/L) measured at the end of the TT did not differ between leg and arm cycling (all P>0.05). After the initial 1/3 of the TT, there was a greater reduction in Pmax for arm cycling compared to leg cycling (20±10 vs. 37±15%, exercise x time P=0.03). However, at the end of the TT, the reduction in Pmax did not differ between leg and arm cycling (45±8 vs. 54±11%, exercise x time p=0.11). At 6.6 post-TT, Pmax had recovered to pre-exercise values for both leg and arm cycling (1±4 vs. 11±14%, simple main effect both P>0.05). CONCLUSION: These preliminary results highlight noticeable differences in the development of fatigue between exhaustive high-intensity endurance exercise involving leg and arm muscle mass. Despite these differences, leg and arm end exercise fatigue were similar between these endurance trained groups and the time courses of recovery for maximal voluntary neuromuscular function generally paralleled one another. Such similarities may reflect PCr resynthesis.

25(OH) Vitamin D Is Associated with Greater Muscle Strength in Healthy Men and Women

The purpose of the study was to examine the relation between serum 25-hydroxy vitamin D (25(OH)D) levels and muscle strength in 419 healthy men and women over a broad age range (20-76 yr). Isometric and isokinetic strength of the arms and legs was measured using computerized dynamometry, and its relation to vitamin D was tested in multivariate models controlling for age, gender, resting HR, systolic blood pressure, diastolic blood pressure, body mass index, maximal oxygen uptake (VO(2max)), physical activity counts, and season of vitamin D measurement. Vitamin D was significantly associated with arm and leg muscle strength when controlling for age and gender. When controlling for other covariates listed previously, vitamin D remained directly related to both isometric and isokinetic arm strength but only to isometric leg strength. These data suggest that there may be a differential effect of vitamin D on upper and lower body strength. The mechanism for this difference remains unclear but could be related to differences in androgenic effects or to differences in vitamin D receptor expression. Our study supports a direct relation between vitamin D and muscle strength and suggests that vitamin D supplementation be evaluated to determine whether it is an effective therapy to preserve muscle strength in adults.

Hemodynamic Responses Following High Intensity Isokinetic Exercise

PURPOSE: To compare the influence of exercise velocity and muscle mass, on hemodynamic responses following an isokinetic exercise protocol. METHODS: Fourteen male volunteers aged (26.9± 3.1 yrs; height 181.8±9.6 cm; weight 81.2±9 kg; BMI 24.6±1.8 kg m−2) performed twenty maximal isokinetic arm or leg contractions (eccentric and concentric) at 60 deg·sec−1, 150 deg·sec−1, and 240 deg·sec−1, administered in randomized order. Immediately following these tests, continuous, non-invasive, beat-by-beat recordings were made of Mean Arterial Pressure (MAP), Cardiac Output (CO), Heart Rate (HR), Stroke Volume (SV). RESULTS: Repeated measures 3-way ANOVA (velocity × muscle group × time) indicated no significant differences in recovery arm MAP across the three velocities. The arm MAP values were significantly higher (P<0.05) than the leg values (114.5±22.4; 107.85±17.65 mmHg). Overall, there was a decline in MAP during the first 30 seconds of recovery. The greatest undershoot of the MAP was seen during the 240 deg·sec−1 condition. The mean CO values following the leg tests were higher than arm tests (12.06±1.8 vs. 10.31±1.6 L•min−1). CO following the 60 deg·sec−1 testing velocity (arm) was lower [P<0.05] (9.49±1.32 L•min−1) than those recorded in the other two velocity conditions (10.72±1.73 L•min−1). Heart rates were significantly higher (125.37±17.85; 133.65±20.04; 136.22±19.12 bts•min−1 during the leg tests. Recovery heart rates in the 60 deg·sec−1 condition were lower (111.9±16.22; 119.62±22.64; 122.06±20.70 bts•min−1)] when compared to the 150 deg·sec−1 and 240 deg·sec−1 testing velocities. At the onset of recovery, the SV tended to be significantly below resting baseline values particularly after the arm tests. Within 10 seconds of recovery the SV tended to overshoot the baseline values and then remained elevated throughout the duration of the 110 second analysis period. Following the 150 deg·sec−1 arm test the SV was significantly higher (P<0.05) any of the other tests (91.11±12.06 vs 87.55±10.27 ml·bt−1). CONCLUSIONS: Recovery hemodynamics following high intensity isokinetic exercise exhibited unique characteristics not clearly indicative of a hypotensive state. These changes appear to be influenced partly by muscle mass and the velocity of movement.

Effects of Robot-Aided Bilateral Force-Induced Isokinetic Arm Training Combined With Conventional Rehabilitation on Arm Motor Function in Patients With Chronic Stroke

Chang J-J, Tung W-L, Wu W-L, Huang M-H, Su F-C. Effects of robot-aided bilateral force-induced arm training combined with conventional rehabilitation on arm motor function in patients with chronic stroke. Objective To analyze the effects of conventional rehabilitation combined with bilateral force-induced isokinetic arm movement training on paretic upper-limb motor recovery in patients with chronic stroke. Design Single-cohort, pre- and postretention design. Setting Rehabilitation department at a medical university. Participants Twenty subjects who had unilateral strokes at least 6 months before enrolling in the study. Intervention A training program (40min/session, 3 sessions/wk for 8wk) consisting of 10 minutes of conventional rehabilitation and 30 minutes of robot-aided, bilateral force-induced, isokinetic arm movement training to improve paretic upper-limb motor function. Main Outcome Measures The interval of pretest, post-test, and retention test was set at 8 weeks. Clinical arm motor function (Fugl-Meyer Assessment [FMA], upper-limb motor function, Frenchay Arm Test, Modified Ashworth Scale), paretic upper-limb strength (grip strength, arm push and pull strength), and reaching kinematics analysis (peak velocity, percentage of time to peak velocity, movement time, normalized jerk score) were used as outcome measures. Results After comparing the sets of scores, we found that the post-test and retention test in arm motor function significantly improved in terms of grip ( P=.009), push ( P=.001), and pull ( P=.001) strengths, and FMA upper-limb scale ( P<.001). Reaching kinematics significantly improved in terms of movement time ( P=.015), peak velocity ( P=.035), percentage of time to peak velocity ( P=.004), and normalized jerk score ( P=.008). Improvement in reaching ability was not sustained in the retention test. Conclusions Preliminary results showed that conventional rehabilitation combined with robot-aided, bilateral force-induced, isokinetic arm training might enhance the recovery of strength and motor control ability in the paretic upper limb of patients with chronic stroke.

Behavioral Intervention, Exercise, and Nutrition Education to Improve Health and Fitness (BENEfit) in Adolescents With Mobility Impairment Due to Spinal Cord Dysfunction

Background/Objective: Determine the effects of a nutrition education and exercise intervention on the health and fitness of adolescents with mobility impairment due to spinal cord dysfunction from myelomeningocele and spinal cord injury. Subjects participated in a 16-week intervention consisting of a behavioral approach to lifestyle change, exercise, and nutrition education to improve fitness (BENEfit) program. Participants were given a schedule of aerobic and strengthening exercises and attended nutrition education and behavior modification sessions every other week along with their parent(s).Subjects: Twenty adolescents (aged 11–18 years, mean 15.4 ± 2.2 years) with spinal cord dysfunction.Methods: Subjects were tested immediately prior to starting and upon completion of the program. Aerobic fitness was measured using a ramp protocol with an arm ergometer. Heart rate and oxygen uptake were measured. Values at anaerobic threshold and maximum oxygen uptake were recorded. Peak isokinetic arm and shoulder strength were determined with a dynamometer. Body composition was estimated with dual–energy x–ray absorptiometry. Serum chemistry included measures of cholesterol, high–density lipoprotein, low-density lipoprotein, and triglycerides.Results: Fourteen individuals completed all testing sessions. There was no significant overall change in weight, body mass index, body mass index z–scores, or serum chemistry. Overall, there was a significant increase in whole body lean tissue without a concomitant increase in whole body fat. Fitness measures revealed a significant increase in maximum power output, work efficiency as measured by the amount of power output produced aerobically, and resting oxygen uptake. Strength measurements revealed a significant increase in shoulder extension strength and atrend towards increased shoulder flexion strength. There were no significant changes in high–density lipoprotein, low–density lipoprotein, total cholesterol, or triglycerides.Conclusions: The BENEfit program shows promise as a method for improving the health and fitness of adolescents with mobility impairments who are at high risk for obesity and obesity-related health conditions.

Insulin-like growth factor-2 genotype, fat-free mass, and muscle performance across the adult life span.

The influence of insulin-like growth factor-2 (IGF2) genotype on total body fat-free mass (FFM), muscle strength, and sustained power (SP) was evaluated repeatedly at approximately 2-yr intervals in two cohorts from the Baltimore Longitudinal Study of Aging. Cohort 1 was comprised of 94 men tested for isometric grip strength and SP. Cohort 2 was comprised of 246 men and 239 women tested for total body FFM and isokinetic peak torque. Subjects were retrospectively genotyped for the IGF2 gene's ApaI polymorphism. Differences between genotype groups for total FFM, strength, and SP at first visit, at peak age (35 yr), at age 65, and across the adult age span were analyzed using either two-sample t-tests or mixed-effects models, depending on the specific comparisons made. Isokinetic arm strength at the time of first visit was lower in A/A men than in G/G men (P < 0.05). Compared with G/G women, A/A women had lower total body FFM, lower isokinetic arm and leg strength at the time of first visit, and lower values at age 35 (all P < 0.05) for these muscle phenotypes. Furthermore, this difference between the genotype groups was maintained at age 65 and across the adult age span (P < 0.05). No genotype-associated differences in rates of loss of grip strength or SP were found in cohort 1. These results from cohort 2 support the hypothesis that variation within a gene known to influence developing muscle affects muscle mass and muscle function in later life.

EMG Power Frequency Spectrum Shifts during Repeated Isokinetic Knee and Arm Movements

EMG Power Frequency Spectrum Shifts during Repeated Isokinetic Knee and Arm Movements