Biomedical subjects

A L Hicks

Publications and source records attributed to A L Hicks.

At least 19 recordsLinked to original sources

PubMed2005

Long-term body-weight-supported treadmill training and subsequent follow-up in persons with chronic SCI: effects on functional walking ability and measures of subjective well-being.

STUDY DESIGN: Longitudinal, prospective within-subject design. OBJECTIVES: (1) To determine the effects of long-term body-weight-supported treadmill training (BWSTT) on functional walking ability and perceived quality of life in persons with chronic incomplete spinal cord injury (SCI), and (2) to investigate whether training adaptations are maintained following cessation of the BWSTT programme. SETTING: Hamilton, Ontario, Canada. METHODS: A group of 14 individuals with chronic (mean 7.4 years postinjury) incomplete SCI (ASIA B & C) participated in thrice-weekly sessions of BWSTT for a period of approximately 12 months (144 sessions). Functional walking ability and indices of subjective well-being were evaluated during the training programme and over an 8-month follow-up. RESULTS: In total, 13 subjects successfully completed the 144 training sessions in the required study period (max. 15 months). Adherence to the thrice-weekly training frequency was 78.8%. All subjects improved in treadmill walking ability (54% reduction in required external body-weight support (BWS), 180% increase in treadmill walking speed, 335% increase in distance walked/session), and six subjects improved their capacity to walk over ground. There were accompanying increases in satisfaction with life and satisfaction with physical function, both of which were significantly correlated with improvements in treadmill walking ability. All but one subject returned for follow-up assessment 8 months post-training; while there was a slight decline in treadmill walking performance, over ground walking scores remained relatively stable. The only change in subjective well-being in the follow-up was a slight decrease in satisfaction with physical function. CONCLUSION: Thrice-weekly BWSTT for 12 months was an effective stimulus to improve treadmill walking ability and indices of subjective well-being in persons with chronic incomplete SCI, and most of these improvements were maintained for up to 8 months following the cessation of training.

Activities of Daily Living↗

PubMed2005

Spasticity after spinal cord injury.

Symptoms of spasticity are often experienced by individuals with spinal cord injury (SCI) following a period of spinal shock and, in many cases, these symptoms negatively affect quality of life. Despite its prevalence, spasticity as a syndrome in the SCI population is not always managed effectively. This is likely due to the fact that the syndrome can have various presentations, each with their own specific etiology. This overview summarizes the symptoms and pathophysiology of the various presentations of spasticity in the SCI population and discusses the currently accepted management techniques. There is a need for a better understanding of the syndrome of spasticity as well as the development of a valid and reliable assessment tool.

Baclofen↗

PubMed2005

Body weight supported treadmill training in acute spinal cord injury: impact on muscle and bone.

DESIGN: Longitudinal prospective case series. OBJECTIVE: To evaluate the impact of early introduction post-spinal cord injury (SCI) of twice-weekly body-weight supported treadmill training (BWSTT) on muscle and bone. SETTING: Centre for Health Promotion and Rehabilitation, McMaster University, Canada. METHODS: Five individuals who had sustained traumatic SCI within 2-6 months participated in the study. Bone mineral densities (BMD) of proximal femur, distal femur, proximal tibia and lumbar spine were measured before and after training, as well as muscle cross-sectional area (CSA), BMD and bone geometry at mid-femur and proximal tibia. Serum osteocalcin and urinary deoxypyridinoline were measured at baseline, and after 24 and 48 sessions of training. RESULTS: All participants experienced increased muscle CSAs, ranging from 3.8 to 56.9%. Reductions in BMD were evident in all participants at almost all lower limb sites after training, ranging in magnitude from -1.2 to -26.7%. Lumbar spine BMD changes ranged from 0.2 to -7.4%. No consistent changes were observed in bone geometry. BWSTT did not alter the expected pattern of change in bone biochemical markers over time. The individual with the greatest improvement in ambulatory ability demonstrated the smallest reduction in lower limb BMD. Conversely, the individual who completed the fewest BWSTT sessions demonstrated the greatest reductions in BMD. CONCLUSIONS: Twice-weekly BWSTT appeared to partially reverse muscle atrophy after SCI, but did not prevent bone loss. Larger, controlled trials should evaluate whether relative preservation of bone loss occurs with regular BWSTT following acute SCI. SPONSORSHIP: Ontario Neurotrauma Foundation.

Adult↗

PubMed2005

The effects of body-weight supported treadmill training on cardiovascular regulation in individuals with motor-complete SCI.

STUDY DESIGN: Four-month longitudinal within-subject exercise training study. OBJECTIVE: Although body-weight supported treadmill training (BWSTT) has not shown promise as a means of improving ambulation in individuals with motor-complete spinal cord injury (SCI), it may still improve cardiovascular health and function in this population. The purpose of this study was to (i) investigate the effects of BWSTT on peripheral muscular and elastic artery dimension and function and measures of heart rate variability (HRV) and blood pressure variability (BPV) in individuals with motor-complete SCI, and (ii) to make a preliminary examination of what factors may predict favourable cardiovascular outcomes following BWSTT in this population. SETTING: Centre for Health Promotion and Rehabilitation, McMaster University, Hamilton, Ontario, Canada. METHODS: Six individuals (four male, two female; age 37.7+/-15.4 years) with chronic SCI (C4-T12; ASIA A-B; 7.6+/-9.4 years post-injury) were included in the present investigation. Doppler ultrasound was used to determine femoral (exercising; muscular), carotid (elastic) and brachial (non-exercising control; muscular) artery dimension and function before and after 4 months of BWSTT. Continuous heart rate and blood pressure were also recorded before and after 4-months of BWSTT to determine frequency domain measures of HRV and BPV; clinically valuable indices of neurocardiac and neurovascular control, respectively. RESULTS: Two-way ANOVA (vessel x time) revealed no exercise-induced change in femoral or carotid artery cross-sectional area, blood flow or resistance and no change in carotid artery compliance following the 4 months of BWSTT compared to the non-exercising control brachial artery. However, there was a significant exercise-induced increase in femoral artery compliance. There were no exercise-induced changes in HRV or BPV when all participants were considered together. However, the results suggest that the subgroup of individuals who had a substantial heart rate response to BWSTT (n=3), experienced exercise-training induced changes in HRV reflective of a relative shift toward cardiac vagal predominance and reductions in BPV. CONCLUSIONS: BWSTT may cause an increase in femoral artery compliance in individuals with motor-complete SCI and therefore, should be encouraged as a means of improving cardiovascular health in this population. BWSTT may also cause modest improvements in measures of HRV and BPV in a select subgroup of individuals who respond to ambulation with moderate to large increases in HR. In the present study, factors associated with a substantial HR response to BWSTT were a propensity to orthostatic intolerance and muscular spasticity.

Adult↗

PubMed2004

Na+,K+-ATPase concentration and fiber type distribution after spinal cord injury.

Complete spinal cord injury (SCI) is characterized, in part, by reduced fatigue-resistance of the paralyzed skeletal muscle during stimulated contractions, but the underlying mechanisms are not fully understood. The effects of complete SCI on skeletal muscle Na(+),K(+)-adenosine triphosphatase (ATPase) concentration, and fiber type distribution were therefore investigated. Six individuals (aged 32.0 +/- 5.3 years) with complete paraplegia (T4-T10; 1-19 years since injury) participated. There was a significantly lower Na(+),K(+)-ATPase concentration in the paralyzed vastus lateralis (VL) when compared to either the subjects' own unaffected deltoid or literature values (from our laboratory, utilizing the same methodology) of VL Na(+),K(+)-ATPase concentration for the healthy able-bodied (141.6 +/- 50.0, 213.4 +/- 23.9, 339 +/- 16 pmol/g wet wt., respectively; P < 0.05). There was also a significant negative correlation between the Na(+),K(+)-ATPase concentration in the paralyzed VL and years since injury (r = -0.75, P < 0.05). These findings are clinically relevant as they suggest that reductions in Na(+),K(+)-ATPase contribute to the fatigability of paralyzed muscle after SCI. Unexpectedly, the VL muscles of our subjects had a higher proportion of their area represented by type I fibers compared to literature values for the VL of the healthy able-bodied (52.6 +/- 25.3% vs. 36 +/- 11.3%, respectively; P < 0.05). As all our subjects had upper motor neuron injuries and, therefore, experienced muscle spasticity, our findings warrant further investigation into the relationship between muscle spasticity and fiber type expression after SCI.

Adult↗

PubMed2003

Long-term exercise training in persons with spinal cord injury: effects on strength, arm ergometry performance and psychological well-being.

STUDY DESIGN: Randomized controlled trial of exercise training in persons with spinal cord injury. OBJECTIVE: The purpose of this study was to examine the effects of 9 months of twice-weekly exercise training on strength, arm ergometry performance, and indices of psychological well-being and quality of life. SETTING: Centre for Health Promotion and Rehabilitation, McMaster University, Hamilton, Ontario, Canada. METHODS: Thirty-four men and women (aged 19-65 years) with traumatic spinal cord injury (C4-L1; ASIA A-D) of 1-24 years duration volunteered to participate, and were randomized into exercise (EX; n=21) and control (CON; n=13) groups. Twenty-three subjects (11 EX; 12 CON) successfully completed the 9-month study. Subjects were assessed for one repetition maximum (1RM) strength, arm ergometry performance, and several indices of quality of life and psychological well-being at baseline, 3, 6, and 9 months. RESULTS: At baseline, there were no significant differences between groups in age, submaximal arm ergometry performance, muscle strength, or psychological well-being. Following training, the EX group had significant increases in submaximal arm ergometry power output (81%; P<0.05), and significant increases in upper body muscle strength (19-34%; P<0.05); no significant changes occurred in CON. Participants in EX reported significantly less pain, stress and depression after training, and scored higher than CON in indices of satisfaction with physical function, level of perceived health and overall quality of life (P<0.05). Exercise adherence (per cent of prescribed sessions attended) in those subjects who completed the 9 months of training was 82.5%. CONCLUSIONS: These results demonstrate that long-term twice-weekly exercise training in this population is feasible, and results in significant gains in both physical and psychological well-being.

Adult↗

PubMed2003

Maintenance of exercise participation in individuals with spinal cord injury: effects on quality of life, stress and pain.

STUDY DESIGN: Follow-up study of seven individuals with spinal cord injury (SCI) who completed a 9-month randomized control trial (RCT) of exercise training. OBJECTIVE: In a 9-month RCT conducted in our lab, individuals with SCI who participated in a twice-weekly supervised exercise training reported greater perceived quality of life (PQOL), and less stress and pain than a nonexercising control cohort. The present follow-up study examined the voluntary continuation of exercise training after the study ended and the persistence of the accrued psychosocial benefits. SETTING: Centre for Health Promotion and Rehabilitation, McMaster University, Hamilton, Ontario, Canada. METHODS: Five men and two women (age 42.3+/-3.6 years) with SCI (C5-T12; ASIA A-D 12.7+/-8.2 years postinjury) were invited to continue supervised exercise training twice weekly at the completion of the 9-month RCT. Exercise adherence, PQOL, stress and bodily pain were measured at a 3-month follow-up and were compared to values obtained at baseline, and at 3, 6 and 9 months during the intervention. RESULTS: There was a significant decrease in adherence at the 3-month follow-up compared to the overall 9-month adherence rate (42.7 versus 80.6%, respectively; P<0.01). There was also a significant decrease in PQOL (P<0.05) and a trend for increased pain (P=0.07) and stress (P=0.12), at follow-up compared to the end of the 9-month trial. Finally, there was a significant negative correlation between pain at the conclusion of the RCT and exercise adherence over the 3-month follow-up period (r=-0.91; P<0.01). CONCLUSIONS: These findings emphasize the importance of continued exercise adherence to the maintenance of exercise-related increases in psychological well-being among individuals with SCI.

Adult↗

PubMed2001

Carbon and char residue yields from rapid pyrolysis of kraft black liquor.

The yields of char residue, fixed carbon, and inorganic carbonate were measured for oxidized black liquor char residues produced in a laboratory laminar entrained-flow reactor (LEFR) at heating rates of 4000-13,000 degrees C/s. The char residue yields at the end of devolatilization thus obtained decreased nearly linearly with temperature, from 75% at 700 degrees C to 58% at 1100 degrees C. There were explainable differences in the char residue yields from the liquor used in this study and those used in other studies. Char residue yields seemed to depend mainly on the temperature to which the particles or droplets were exposed and were not very sensitive to heating rate. Fixed carbon yields behaved similarly to those of the char residue. The fixed carbon remaining at the end of devolatilization decreased from 67% at 700 degrees C to about 45% at 1100 degrees C. The carbonate content in black liquor changed very little before and after devolatilization.

Carbon↗

PubMed2001

Sex differences in human skeletal muscle fatigue.

Research on muscle fatigue suggests that greater fatigue resistance may be evident in females compared with males. The possible mechanisms for this sex difference include factors related to muscle mass, substrate utilization, muscle morphology, and neuromuscular activation.

Adult↗

PubMed2001

Protein kinase C inhibits insulin-induced Akt activation in vascular smooth muscle cells.

Protein kinase C (PKC) activation, enhanced by hyperglycemia, is associated with many tissue abnormalities observed in diabetes. Akt is a serine/threonine kinase that mediates various biological responses induced by insulin. We hypothesized that the negative regulation of Akt in the vasculature by PKC could contribute to insulin resistant states and, may therefore play a role in the pathogenesis of cardiovascular disease. In this study, we specifically looked at the ability of PKC to inhibit Akt activation induced by insulin in cultured rat aortic vascular smooth muscle cells (VSMCs). Activation of Akt was determined by immunoblotting with a phospho-Akt antibody that selectively recognizes Ser473 phosphorylated Akt. A PKC activator, phorbol 12-myristate 13-acetate (PMA), inhibited insulin-dependent Akt phosphorylation. However, PMA did not inhibit platelet-derived growth factor (PDGF)-induced activation of Akt. We further showed that the PKC inhibitor, G06983, blocked the PMA-induced inhibition of Akt phosphorylation by insulin. In addition, we demonstrated that PMA inhibited the insulin-induced tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1). From these data, we conclude that PKC is a potent negative regulator of the insulin signal in the vasculature, which indicate an important role of PKC in the development of insulin resistance in cardiovascular disease.

Animals↗

PubMed2000

The effect of age and gender on the relative fatigability of the human adductor pollicis muscle.

The purpose of this study was to examine the relative influence of such factors as age, gender, and absolute force on the fatiguability of the human adductor pollicis muscle. 12 young males (YM, 25.3 +/- 2.1 y), 12 young females (YF. 23.5 +/- 2.1 y), 12 older males (OM, 71.7 +/- 5.6 y) and 12 older females (OF, 69.5 +/- 4.6 y) participated. Three minutes of intermittent (5 s contraction, 2 s rest) maximal voluntary contractions (MVC) were used to fatigue the adductor pollicis muscle; the ulnar nerve was also stimulated in each 2 s rest period to evoke a maximal twitch. Males were stronger than females in both voluntary and evoked force (PT) in the young age group (MVC: YM, 10.0 +/- 2.7 kg vs. YF, 6.6 +/- 1.1 kg, P < 0.05) (PT: YM, 0.99 +/- 0.21 kg vs. YF, 0.71 +/- 0.12 kg, P < 0.05). In the older adults, however, males were stronger only in the evoked twitch (OM, 0.73 +/- 0.24 kg vs. OF, 0.48 +/- 0.07 kg, P < 0.05). There was no significant effect of gender or absolute muscle force on relative fatigability; the only variable found to significantly affect fatigability was age. Older adults were significantly less fatigable than young adults as indicated by the voluntary fatigue index (FI) (percentage of force reduction from baseline; FI-young, 40.2 +/- 12.6% vs. FI-old, 25.2 +/- 12.3%). This age effect, however, was more prominent in males than females (FI-YM, 44.7 +/- 10.5% vs. FI-OM, 24.2 +/- 10.7%, P < 0.01; FI-YF, 37.8 +/- 14.1% vs. FI-OF, 26.3 +/- 14.5%, P = 0.13). In conclusion, age was found to be the strongest single predictor of fatigability during short duration, intermittent exercise in human adductor pollicis muscle.

Adult↗

PubMed1998

Muscle performance and enzymatic adaptations to sprint interval training.

Our purpose was to examine the effects of sprint interval training on muscle glycolytic and oxidative enzyme activity and exercise performance. Twelve healthy men (22 +/- 2 yr of age) underwent intense interval training on a cycle ergometer for 7 wk. Training consisted of 30-s maximum sprint efforts (Wingate protocol) interspersed by 2-4 min of recovery, performed three times per week. The program began with four intervals with 4 min of recovery per session in week 1 and progressed to 10 intervals with 2.5 min of recovery per session by week 7. Peak power output and total work over repeated maximal 30-s efforts and maximal oxygen consumption (VO2 max) were measured before and after the training program. Needle biopsies were taken from vastus lateralis of nine subjects before and after the program and assayed for the maximal activity of hexokinase, total glycogen phosphorylase, phosphofructokinase, lactate dehydrogenase, citrate synthase, succinate dehydrogenase, malate dehydrogenase, and 3-hydroxyacyl-CoA dehydrogenase. The training program resulted in significant increases in peak power output, total work over 30 s, and VO2 max. Maximal enzyme activity of hexokinase, phosphofructokinase, citrate synthase, succinate dehydrogenase, and malate dehydrogenase was also significantly (P < 0.05) higher after training. It was concluded that relatively brief but intense sprint training can result in an increase in both glycolytic and oxidative enzyme activity, maximum short-term power output, and VO2 max.

Adaptation, Physiological↗

PubMed1997

An evaluation of the length-tension relationship in elderly human plantarflexor muscles.

The purpose of this study was to determine the effect of aging on the muscle length-tension relationship in the plantarflexor muscles of 10 subjects aged 20-30 yr (Mean = 23; 5 males, 5 females), 10 subjects aged 60-80 yr (Mean = 72.3; 5 males, 5 females), and 10 subjects over 80 yr (Mean = 84.1, 5 males, 5 females). Isometric twitch properties, maximum voluntary strength, passive tension, and range of motion were measured at five different joint angles [20 degrees dorsiflexion (DF), 10 degrees DF, 0 degree, 10 degrees plantarflexion (PF), and 20 degrees PF]. Active (evoked and voluntary) and passive torque production were maximal when the ankle was rotated into the DF positions for all three age groups, whereas the lowest values were recorded when the ankle was rotated into 20 degrees PF. Males were stronger than females at all joint angles (p < .01). Also, young adults were stronger than both elderly adult groups (p < .01). These results illustrate that despite the considerable age-associated loss in both voluntary and evoked strength in the plantarflexors, the optimal angle for torque production remains the same for younger and older adults.

Adult↗

PubMed1996

A 12-year follow-up study of ankle muscle function in older adults.

The purpose of this study was to examine changes in strength over time in a cohort of healthy elderly people who underwent assessments of ankle muscle function 12 years earlier. The isometric strength and contractile characteristics of the dorsiflexors and plantarflexors were studied in 11 male and 11 female subjects, ranging from 73-97 yrs (mean age 84 +/- 7.1 yrs). The same footplate apparatus was used as during the original testing. From 1982 to 1994, plantarflexor strength decreased 2.1% per year in females, and 2.5% per year in males (p < .01). The loss was relatively less in the dorsiflexor muscles; strength decreased 0.3% per year in females, and 0.8% per year in male (p > .05). There were no significant changes in evoked twitch torque in either muscle group, which may be due to the fact that passive tension of the connective tissue increased (p < .01) over the 12-year period. We conclude from this longitudinal assessment of ankle muscle function that the rate of loss of voluntary strength can vary considerably between antagonistic muscle groups. Factors influencing this variable loss warrant further investigation.

Aged↗

PubMed1996

A longitudinal trial of weight training in the elderly: continued improvements in year 2.

We conducted a 2-year (42 weeks of consecutive training in each year, separated by 10 weeks of testing and vacation time) randomized, controlled trial of weight training in 142 healthy male and female subjects, aged 60 to 80 years. Measurements included dynamic strength, symptom-limited endurance in cycling, treadmill walking and stair climbing, muscle size, and bone mineral density and content of the lumbar spine and whole body. One hundred and thirteen subjects completed the study (57 exercise, 56 control), with a mean attendance of 85% among the exercisers. Muscle strength was unchanged in the control subjects but increased (collapsed across age and gender) from 32% (leg press) to 90% (military press) in the exercisers. Symptom-limited endurance in cycling, treadmill walking, and stair climbing increased in the exercisers by (mean +/- SE) 6.2 +/- 0.8%, 29.2 +/- 7.3%, and 57 +/- 12%, respectively; the only change in the controls was an unanticipated 33% increase in stair climbing performance during the first year. These values were unchanged in the controls. Cross-sectional area of the knee extensors increased by 8.7 +/- 0.9% in the trained subjects and was unchanged in controls. Measures of whole body, lumbar spine bone mineral density, and lumbar spine bone mineral content were unchanged in the exercisers, but whole body bone mineral content decreased by 1%. In contrast, there were small increases (< 4.0%) in bone mineral density among the controls. Long-term weight training proved to be a safe and well-tolerated mode of exercise for the elderly. Increased strength was associated with muscle hypertrophy in each year, and with increased endurance in cycling, walking, and stair climbing. There were no changes in bone mineral density but a small reduction in whole body bone mineral content.

Aged↗

PubMed1996

Gender differences in isometric contractile properties and fatigability in elderly human muscle.

This study had two purposes: to compare the isometric contractile characteristics and fatigability in the elbow flexors (EF) and ankle dorsiflexors (DF) in older males and females (60-80 years), and to determine the effects of almost 2 years of twice weekly dynamic weight-lifting training on these properties One hundred nine male and female subjects completed the 22-month intervention, 54 in the exercise group and 55 in the control group. Isometric contractile properties and fatigue characteristics were assessed at baseline, 10 months, and 22 months. At baseline, males were significantly stronger (p < .05) than females in evoked twitch torque (Pt) and maximal voluntary strength (MVC) in both EF and DF. Females exhibited significantly less fatigue (expressed either absolutely or relatively) than males in both Pt and MVC during a 3-min protocol of intermittent MVCs (5 s contraction; 2 s rest). There were no significant effects of the 22 months of dynamic training on either the isometric contractile properties or the fatigue characteristics, suggesting a very strong and persistent specificity of training effect.

Aged↗

PubMed1995

Long-term resistance training in the elderly: effects on dynamic strength, exercise capacity, muscle, and bone.

We examined the effects of 42 weeks of progressive weight-lifting training on dynamic muscle strength, peak power output in cycle ergometry, symptom limited endurance during progressive treadmill walking and stair climbing, knee extensor cross-sectional areas, and bone mineral density and content in healthy males and females aged 60-80 years, currently enrolled in a 2-year resistance training program. Subjects were randomized into either exercise (EX) or control (CON) groups (60-70 years: 38 males and 36 females; 70-80 years: 25 males and 43 females). EX trained several muscle groups twice per week for 42 weeks at intensities ranging from 50-80% of the load that they could lift once only (1 RM); CON did usual daily activities. After the 10 months there was no change in 1 RM strength in CON, but significant gains (mean increases up to 65%) in EX (no independent age or gender effects); 30% and 47% of the increase in 1 RM had occurred by 6 and 12 weeks, respectively. In EX, the 7.1% increase in peak cycling power output was significantly greater than in CON (+1.1%). The 17.8% improvement in symptom limited treadmill walking endurance was also greater than in CON (+3.4%), but the difference between groups during stair climbing was not significant (EX + 57%, CON + 33%). The cross-sectional areas of the knee extensors increased significantly by 5.5% in EX but were unchanged in CON. There were no changes in bone mineral density or content in either group. We conclude that long-term resistance training in older people is feasible and results in increases in dynamic muscle strength, muscle size, and functional capacity.

Aged↗

PubMed1994

An evaluation of the length-tension relationship in elderly human ankle dorsiflexors.

Aging is thought to be associated with a decreased elasticity of skeletal muscle, which may be predicted to affect the optimal length at which peak tension is developed. This was assessed in the present study, in which we examined the effect of aging on the muscle length-tension relationship in the right ankle dorsiflexors of 60 subjects aged 20-40 years (M = 25.3; 15 males, 15 females) and 60-80 years (M = 68.8; 15 males, 15 females). Evoked contractile properties, 1-sec tetanic contractions (at 20, 50, and 80 Hz), and maximal voluntary contractions (MVC) were measured at 10 joint angles (15 degrees dorsiflexion to 30 degrees plantarflexion, in 5 degrees increments). Peak twitch torque occurred at the extreme of plantarflexion (30 degrees P) in both elderly and young adults, and although males had significantly greater twitch torques than females, there was no difference between the elderly and young adults. Maximum tetanic torque and MVC torque occurred at 30 degrees P and 20 degrees P, respectively, but in this case the young adults were significantly stronger than the elderly adults, and the males stronger than the females at all joint angles. There was no difference in the torque-angle relationship between elderly and young adults in any of the evoked or voluntary measures. At each of the three frequencies, the rise time of tetanic torque was also similar between elderly and young adults. These results suggest that any age-related change in the elastic properties of the ankle dorsiflexors does not affect the length (as inferred by joint angle)-tension relationship in this muscle group.

Adult↗