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PubMed1999

Effects of 30 days of creatine ingestion in older men.

In this investigation we evaluated the effects of oral creatine (Cr) supplementation on body composition, strength of the elbow flexors, and fatigue of the knee extensors in 20 males aged 60-82 years who were randomly administered Cr or placebo (P) in a double-blind fashion. Subjects ingested either 20 g of Cr or P for 10 days, followed by either 4 g of Cr or P, respectively, for 20 days. Tests were conducted pre-supplementation and following 10 and 30 days of supplementation. Leg fatigue was determined using an isokinetic dynamometer; subjects performed 5 sets of 30 maximal voluntary contractions at 180 degrees x s(-1), with 1 min of recovery between sets. The strength of the elbow flexors was assessed using a modified preacher bench attached to a strain gauge. There was a significant interaction (P < 0.05; group x time) in leg fatigue following supplementation. However, this interaction appears to have resulted from a combination of the improved fatigue score by the Cr-supplemented group and the decreased fatigue score by the P-supplemented group, because when the simple main effects were analyzed for the groups individually, there was no significant difference over time for either of the groups. There were no significant differences in body mass, body density, or fat-free mass as assessed by hydrostatic weighing, or strength between the Cr-supplemented or P-supplemented groups. These data suggest that 30 days of Cr-supplementation may have a beneficial effect on reducing muscle fatigue in men over the age of 60 years, but it does not affect body composition or strength.

Aged↗
PubMed1998

Evaluation of the ability of power to predict low frequency lifting capacity.

An experiment was conducted to examine the role that maximal lifting power has in predicting maximum acceptable weight of lift (MAWL) for a frequency of one lift per 8 h. The secondary aim of the study was to compare the ability of power to predict MAWL to previously used measures of capacity including two measures of isometric strength, five measures of isokinetic strength, and isoinertial capacity on an incremental lifting test. Twenty-five male subjects volunteered to participate in the experiment. The isometric tests involved maximum voluntary contractions for composite lifting strength at vertical heights of 15 and 75 cm. Peak isokinetic strength was measured at velocities of 0.1, 0.2, 0.4, 0.6 and 0.8 m s-1 using a modified CYBEX II isokinetic dynamometer. Isoinertial lifting capacity was measured on the X-factor incremental lifting machine and peak power was measured on the incremental lifting machine by having subjects lift a 25 kg load as quickly as possible. The results indicate that peak isoinertial power is significantly correlated with MAWL, and this correlation was higher than any of the correlations between the other predictor variables and MAWL. The relationships between the isokinetic strength measures and MAWL were stronger than the relationships between the isometric measures and MAWL. Overall, the results suggest that tests used to predict MAWL should be dynamic rather than static.

Adult↗
PubMed2001

[Isokinetic diagnosis: rehabilitation in overuse injury syndromes].

Isokinetic testing of the musculoskeletal system is an important diagnostic method in the course of rehabilitation because it is adapted to individual and objective in measuring biomechanical parameters. Isokinetic dynamometer serves as a measurement and/or exercising device and helps user to achieve maximum force in through a range of motion, accommodating for potential pain or fatigue. Isokinetic dynamometer measures strength, torque, and generated power as well as the range of motion of the joint and distribution of strength in the range of motion. These results, as well as the relation between agonists and antagonists, acceleration time, velocity of motion reciprocity, maximum torque angle, and the fatigue/endurance index are computed and compared with standard values using software. Repeated testing shows changes in parameters in later stages, ensuring an accurate insight in the progress of rehabilitation. This paper describes the treatment of a 14-year-old boy engaged in rowing who suffered from suprapatellar pain and instability of the knee. After isokinetic testing and rehabilitation the boy resumed his sport activities.

Adolescent↗
PubMed1988

Handgrip strength after the Blalock-Taussig shunt: 14 to 34 year follow-up.

To determine the long-term functional impact of the Blalock-Taussig (BT) shunt, we studied handgrip strength in 56 patients (10-28 years) following total repair of tetralogy of Fallot. Of the 56, 16 (29%) had a previous right BT shunt, 5 of 56 (9%) had a previous left BT shunt, and the remaining 35 patients either had a Potts shunt or primary total repair. The mean age at the time of right BT was 2.8 +/- 1.6 (SD) years, left BT 1.7 +/- 1.2 years, and total repair for all patients was 7.1 +/- 2.2 years. Mean age at the time of study was 26 +/- 9 years. Right-and left-handgrip strength were measured with a Jamar dynamometer, averaging the results of grip position 2, 3, and 4 to accommodate variation in hand size. Since absolute values of hand strength were strongly associated with sex (p = 0.006) and body surface area (p = 0.016), we calculated the ratio of right-hand to left-handgrip strength (RL ratio). The RL ratios were: 0.98 +/- 0.13 (right BT), 1.21 +/- 0.11 (left BT), and 1.13 +/- 0.16 (no BT): (p = 0.004 right BT vs. no BT, p = 0.07 left BT vs. no BT, Wilcoxon rank sum test). Thus, although frequently clinically inapparent, handgrip strength tested many years post-BT shunt is reduced on the side of the shunt.

Adult↗
PubMed1994

Maximal isometric force and muscle cross-sectional area of the forearm in fencers.

The maximal isometric force (MIF) of a muscle is directly related to its cross-sectional area (CSA). Strength training produces an increase in muscular force while muscular hypertrophy becomes appreciable at a later time; in asymmetric sports, training causes significant increases in force and muscular mass of the dominant limb of the athlete. The aim of this study was to analyse the differences in muscular force and trophism between the dominant and non-dominant forearms in fencers and in controls. The data of 17 male distance runners (age 21.4 +/- 2.4 years, body mass 74.0 +/- 5.0 kg, height 180 +/- 6 cm) were compared with those of 58 male fencers (age 23.0 +/- 6.7 years, body mass 71.9 +/- 9.3 kg, height 178 +/- 7 cm) drawn from the ranking lists of the National Fencing Committee. They trained for a mean of 11.4 +/- 6.0 (range 2-36) years, commencing at 10.7 +/- 4.5 years of age. Cross-sectional area (muscle plus bone) was estimated in the dominant and non-dominant forearm using a simplified anthropometric method. Maximal isometric force was determined using a mechanical handgrip dynamometer. The differences in CSA and isometric force between the two limbs and between fencers and controls were tested using paired and unpaired Student's t-tests, respectively. Significant differences in CSA and maximal force were observed between the dominant and non-dominant forearm in fencers (both P < 0.001) and in controls (P < 0.005 and P < 0.001, respectively). The fencers showed a greater CSA (P < 0.001) and force (P < 0.001) in the dominant forearm compared with the control group. Furthermore, the differences between the dominant and non-dominant limb of the fencers were significantly greater than the differences between the dominant and non-dominant limb of the controls (P < 0.001 for CSA and P < 0.05 for force). No significant differences in stress ratio (force/CSA) were obtained in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2000

Assessment of functional outcome after nerve repair in a longitudinal cohort.

To investigate the temporal changes in the results of clinical tests of the functional outcome after nerve repair, we followed up 19 patients periodically over a four year period after repair of the median or ulnar nerve at the forearm. Between the first and last follow-up four of the instruments used--Semmes-Weinstein monofilaments, manual muscle testing, Sollerman grip test, and Jamar dynamometer--indicated significant and moderate to large improvements. A moderate and significant improvement was also noted during the same period in patients' estimation of pain or discomfort. Results of the two-point discrimination test did not change significantly over time. Most changes occurred during the first postoperative year, and thereafter it was principally motor function that improved. We conclude that four of the six used tests showed useful temporal dynamics during the follow-up time. The lack of responsiveness in two-point discrimination test suggests that other or complementary test instruments should be used for assessment of tactile gnosis after nerve repair.

Adolescent↗
PubMed1996

Is salmeterol ergogenic?

OBJECTIVE: To assess the effects of 50 micrograms of inhaled salmeterol on pulmonary function, selected physical capacities, and fine motor control in 16 nonasthmatic male cyclists and triathletes, mean age of 23.2 (SD = 3.5) years. DESIGN: Randomized double-blind placebo-controlled crossover trial. SETTING: Human Physical Performance Laboratory, the University of Western Australia. SUBJECTS: Sixteen healthy male high-performance nonasthmatic athletes with a mean age of 23.2 years participated in the study. INTERVENTION: Subjects attended three experimental testing sessions at which salmeterol (50 micrograms), a placebo, or "no treatment" was administered in random order in a double-blind fashion, on separate occasions, prior to exercise. MAIN OUTCOME MEASURES: During each testing, session lung function was measured before and 10 min after the treatment. Tests of reaction time and hand steadiness and then two anaerobic cycle tests followed. The first, a 10-s all-out sprint was followed, after a 3-min rest, by a 30-s all-out sprint performed on a front access bicycle ergometer. After 10 min recovery, leg flexion-extension peak torque was measured on a Biodex isokinetic dynamometer at speeds of 120 and 180 degrees s-1. MAIN RESULTS: Lung function variables, reaction time, movement time, alactic anaerobic power, lactacid anaerobic power, and leg-flexion and leg-extension muscular strength were similar among the three treatment groups. CONCLUSIONS: The preexercise administration of 50 micrograms of inhaled salmeterol has no performance-enhancing effects in nonasthmatic athletes. We believe that athletes with asthma should be permitted to use salmeterol before competition.

Administration, Inhalation↗
PubMed2003

Taiji training improves knee extensor strength and force control in older adults.

The purpose of this study was to examine the effects of Taiji training on knee extensor strength and force control in older individuals. Twenty-six healthy older adults (71.9 +/- 1.8 years) participated in the study. Sixteen of the older adults (70.2 +/- 1.8 years) underwent Taiji training for 20 weeks (experimental group), whereas the other 10 (74.6 +/- 1.2 years) served as the control group. For both groups, strength and force control of the knee extensors was assessed twice with an isokinetic dynamometer. Strength was assessed with a maximum voluntary isometric contraction (MVC). Force control was measured as the standard deviation (SD) and coefficient of variation (CV) of force during a constant isometric knee extension task at 2%, 30%, 60%, and 90% MVC. For the experimental group, MVC significantly increased (19.5 +/- 4.9%) and the CV of force decreased (18.9 +/- 3.3%) following Taiji training. Improvements in the CV of force were primarily due to decreases in the SD of force (R(2) =.86) rather than increases in strength (R(2) =.12). Furthermore, decreases in SD of force were independent of improvements in strength. For the control group, strength, SD, and CV of force were not different for the 2 tests. The overall findings suggest that Taiji training improves knee extensor strength and force control in older adults.

Aged↗
PubMedDate not supplied

Multidirectional analysis of maximal voluntary contractions of the thumb.

A multidirectional dynamometer was used to investigate the maximal static force (MSF) exerted at the proximal phalanx of the dominant and nondominant thumbs of 12 normal women subjects. These MSFs were measured in two sessions within a two-week interval. Eight directions covering 360 degrees, at increments of 45 degrees within the transverse plane of the longitudinal axis of the thumb, were examined. A three-way analysis of variance (ANOVA) with repeated measures (factors: direction, session, handedness) was performed. No significant interaction was found between the main factors. The ANOVA showed that MSFs vary according to the direction of effort. No significant difference, however, was observed between the dominant and nondominant thumbs or between the MSFs obtained in the two sessions. Post-hoc analysis revealed that MSFs exerted in directions containing an abduction component were significantly lower than MSFs exerted in the other directions. It is concluded that directional strength of the thumb is maximized for functional grasping activities and reflects the anatomic distribution of muscles acting at the thumb.

Adult↗
PubMed1989

Detection of submaximal effort by use of the rapid exchange grip.

To assist in distinguishing patients with truly decreased hand grip strength from those deliberately not gripping the dynamometer at maximal capacity, a rapid exchange grip strength test was devised and tested under four conditions. Part I, 100 normal subjects undergoing static grip testing and the rapid exchange grip test. Part II, 45 patients chosen at random from physical therapy with various hand injuries tested using only the static grip test. Part III, a blind control study on 15 normal subjects instructed to fake an injury to either the right or left hand. This group was given both the static and rapid exchange grip test. Part IV, a retrospective evaluation of 45 patients seen in a private hand practice who had both the static and rapid exchange grip test. After the dynamometer had been set to the position at which the patient had previously achieved maximal grip strength, the patient was instructed to rapidly alternate hands while gripping the dynamometer. Uninjured subjects had consistently lower rapid exchange grip test scores than previous scores at the same setting (negative rapid exchange grip). Average rapid exchange grip test scores were higher than previous scores (positive rapid exchange grip) when subjects were instructed to fake an injury with one hand. We conclude that if maximal performance has not been achieved on the static test, the rapid exchange grip shows a significant increase in grip strength on the affected side. More patients claiming worker's compensation had positive rapid exchange grips and the average score was higher than that of patients not claiming worker's compensation.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed2004

Quadriceps atrophy: to what extent does it exist in patellofemoral pain syndrome?

BACKGROUND: Quadriceps atrophy is a commonly cited accompaniment to patellofemoral pain syndrome (PFPS), yet there is little valid, objective evidence for its existence. OBJECTIVE: To investigate atrophy and weakness of the quadriceps femoris muscle group in patients with PFPS using measures of cross-sectional area and peak extension torque. METHODS: A total of 57 patients with insidious onset of PFPS and 10 healthy control subjects had ultrasound scanning of the quadriceps femoris. The scans were analysed using computerised planimetry to estimate the cross-sectional area of the quadriceps femoris. Lower limb peak torque was also measured using a Biodex dynamometer. RESULTS: The mean of % differences revealed a 3.38% (95% confidence interval (CI) 1.3 to 5.45) difference in cross-sectional area (CSA) between the affected and unaffected limb in PFPS patients and a 1.31% (95% CI 0.06 to 2.55) difference in the dominant and non-dominant limb of the control group; the between-groups difference was not significant (p = 0.409). There was a 18.4% (95% CI 13 to 23.8) difference between the affected and unaffected limb in peak torque in PFPS patients and a 7.6% (95% CI 3.2 to 12) difference between the dominant and non-dominant limb in the control group; the between-groups difference was significant (p = 0.002). CONCLUSIONS: The mean of % differences of 3.38% quadriceps atrophy between limbs was considerably less than the only other study using ultrasound scanning on the quadriceps in PFPS and was not significant between the groups. There were greater and more significant between-group differences in lower limb peak torque indicating that muscle strength may not be related to muscle size. These results help to re-appraise of the amount of quadriceps atrophy in PFPS.

Adult↗
PubMed1998

The effect of bracing on extension strength in patients with ACL insufficiency.

One of the problems following an anterior cruciate ligament (ACL) injury is to regain strength. We tested 11 patients (5 men, 6 women), mean age 28.4 years, with unilateral ACL insufficiency, with two braces (Donjoy Legend, and Bledsoe Brace Force III) versus a placebo brace. The patients were tested on a Biodex Dynamometer at 60 and 180 deg/s in an isokinetic mode. The experiment was designed as a comparative study in a cross-over design with the stable knee as the patient's own control. We found no statistically significant effect of the two braces compared to a placebo brace under the test conditions, and no correlation between knee laxity and the effect of bracing.

Adult↗
PubMed1999

A study of repeated lateral pinch grip in myotonic dystrophy.

BACKGROUND AND PURPOSE: Subjects with myotonic dystrophy present with progressive muscle weakness, myotonia and fatigue. The aim of this study was to determine whether there was a difference in response to fatiguing exercise in myotonic dystrophy individuals compared to normal subjects. If no difference was found, a similar response to a physiotherapy exercise programme as seen in normal subjects might be expected. METHOD: Ten individuals with myotonic dystrophy were compared to eight normal subjects in their response to ten repetitions of maximal lateral pinch grip efforts each five seconds in duration and separated by a ten-second rest. The root mean square (RMS) values, initial median frequency (Fmed) and slope of the median frequencies were recorded by electromyography (EMG) for the first dorsal interosseus, flexor pollicis brevis, flexor digitorum profundus and extensor digitorum communis muscles in the forearm and hand. Simultaneously, the rate of grip development, rate of grip release and work done during each grip effort were recorded by dynamometer. The RMS values for all muscles from subjects with myotonic dystrophy increased over the ten repetitions. RESULTS: The initial Fmed for all myotonic dystrophy muscles was lower than for the normal subjects. The Fmed slopes for the first and last repetition showed no significant difference to the normal subjects. Rate of grip development was no different between groups over ten repetitions. Rate of grip release was slower and work done less for the individuals with myotonic dystrophy. CONCLUSION: Results suggest the main difference between muscles affected by myotonic dystrophy and normal ones was the smaller size of muscle fibres. The increase in rate of grip release that was found is supportive of the 'warm-up' phenomenon. This appears to indicate that muscles affected by myotonic dystrophy could benefit from standard physiotherapeutic exercise methods.

Adult↗
PubMed1999

Is there a relationship between balance, gait performance and muscular strength in 75-year-old women?

OBJECTIVE: To see if there is a relationship between clinical and laboratory tests of balance, muscular strength and gait in elderly women. DESIGN: A randomized population-based study. SETTINGS: Malmö, Sweden. METHODS: We investigated balance with a simple test of standing on one leg, as well as a computerized balance platform. Muscular strength was tested by computerized dynamometer. Extension and flexion of the knee and dorsiflexion of the ankle were tested. We measured the time and number of steps taken to walk a certain distance and the subjects' height and weight. PARTICIPANTS: 418 randomly selected 75-year-old women, of whom 230 took part. RESULTS: There was no relation between the computerized balance tests and any of the other tests. The non-computerized balance test was correlated with gait time and number of steps (r = -0.50, P<0.001 and r = -0.40, P<0.001, respectively). Tests of extension and flexion, strength of the knee and ankle dorsiflexion were related to gait, speed and number of steps. Heavy women had poorer balance when assessed by the non-computerized test (r = -0.32, P<0.001) and with the computerized, stable platform, eyes-open test (r = 0.27, P<0.001) and eyes-closed test (r = 0.44, P<0.001). The heavier an individual was, the slower her gait and the shorter her steps, despite having stronger knee muscles. CONCLUSION: There is no relationship between the simple balance tests and computerized platform tests. Muscle strength of the leg is not necessarily linked to balance, but rather to gait performance.

Aged↗
PubMed1977

Isokinetic and isometric torque force relationships.

The torque forces of elbow extensor musculature of 28 men were tested with an isokinetic dynamometer to determine the relationships between maximal isokinetic torque generated at various speeds and maximal isometric forces at specified angles in the arc of elbow extension. The men were tested at constant velocities ranging from 5 to 25 rpm and at angles of elbow extension ranging from 10 degrees to 90 degrees. Product-moment correlation coefficients were calculated between the maximum isometric torque developed at each of the measured angles and the isokinetic torque generated at each of the predetermined speeds. Of the 81 correlation coefficients calculated, 13 differed significantly from zero. There were slight tendencies for the significant correlations to cluster toward the slower speeds and toward the greater angles of elbow flexion. It was suggested that the slight tendency for higher correlations to cluster toward the slower speeds may be due to slower speeds stimulating isometric effort. The slight tendency for the higher correlations to cluster toward the greater angles of elbow flexion may be due to variances in the consistency of muscular strength at different muscle lengths. Since the highest correlation attained yielded a common variability of less than 24% between the two variables tested, it was concluded that measures of isokinetic strength cannot be used to predict isometric strength capabilities.

Adult↗
PubMedDate not supplied

Phase I design and evaluation of an isometric muscle reeducation device for knee osteoarthritis rehabilitation.

Our long-term goal is to improve adherence to a home-based isometric program for rehabilitation of knee osteoarthritis (OA) using a force-biofeedback device (Isopad). Our goal for Phase I was to design and evaluate an Isopad-based program in a supervised clinical setting. Our subjects were five patients with knee OA of Kellgren stage II or greater. A capacitive force sensor was tested for accuracy, repeatability, and durability. An Arthritis Foundation home-based isometric program inspired the Isopad design. The Isopad provided visual and auditory feedback instantaneously and continuously about force generated between the ankles. The five subjects completed a supervised 8-week progressive isometric program using the Isopad. Absolute isolated quadriceps and hamstring torques were quantified with a dynamometer, and patients completed a self-assessment of symptoms (Western Ontario and McMaster Universities Osteoarthritis Index). The capacitive sensor accuracy error averaged 10% and repeatability 4%. Cognitively intact subjects used the Isopad successfully for isometric progressive resistance training. Quadriceps and hamstrings absolute torques increased an average of 30%. Patients reported decreased functional complaints (Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index). All changes were trends. The Isopad helped subjects with knee OA adhere to a supervised isometric program and meet progressive strength targets. The next-generation Isopad will be employed in a home-based program.

Electromyography↗
PubMedDate not supplied

Longitudinal hand grip and pinch strength recovery in the child with burns.

Hand strength of seven patients was evaluated prospectively. A range-of-motion exercise program, compression therapy, and splinting schedules were provided. Fine prehension; lateral, tip-to-tip, and tripod pinch were measured by pinch meter. Grip strength was measured by dynamometer. Comparisons were made between test strengths and published norms for age and sex with analysis of variance. Significance was accepted at p < 0.05. At discharge, all four strength measurements were significantly less than normal for age and sex. Grip and tripod strengths were improved by 6 weeks. All measurements were improved at 6 months after discharge, although grip and lateral pinch remained significantly less than norms. In conclusion, the measurements of tip-to-tip and tripod pinch at 6 months may not signify limitations in performance of activities of daily living. In spite of significantly lower than normal grip and lateral strength measurements at 6 months, it cannot be determined whether this hinders performance of daily living skills.

Burns↗
PubMed1996

Step length reductions in advanced age: the role of ankle and hip kinetics.

BACKGROUND: Aging is associated with a reduction in gait velocity, which is due to a shortened step length. This study investigated the relationship between joint kinetics and step length. METHODS: Three-dimensional gait kinematics and kinetics were measured during usual pace gait in 26 older subjects (average age 79) and in 32 young subjects (average age 26). Gait measures were obtained at maximal velocity in five older subjects. Lower extremity strength was measured in the older subjects on an isokinetic dynamometer. RESULTS: Older persons had a 10% shorter step length during usual gait, when corrected for leg length (.65 +/- .07, .74 +/- .04/leg length, respectively, p < .001). Older persons had reduced ankle plantarflexion during late stance (13 +/- 5 degrees, 17 +/- 5 degrees, p = .02) and lower ankle plantarflexor power (2.9 +/- 0.9 W kg-1, 3.5 +/- 0.9 W kg-1, respectively, p = .007). Ankle strength was associated with plantarflexor power developed during late stance (r = .49, p < .001). When gait kinetics were corrected for step length, the older subjects developed 16% greater hip flexor power during late stance than younger subjects (estimate of effect: .15 W kg-1, p = .002). Older subjects were unable to increase ankle plantarflexor power at maximal pace, but increased hip flexor power 72% (1.1 +/- 0.3 W kg-1 to 1.9 +/- 1.0 W kg-1, p = .02). CONCLUSIONS: Older subjects had lower ankle plantarflexor power during the late stance phase of gait and appeared to compensate for reductions in plantarflexor power by increasing hip flexor power. Appropriate training of ankle plantarflexor muscles may be important in maintaining step length in advanced age.

Adolescent↗