A novel approach to ageing studies assessed the discriminatory ability of a combination of routin... more A novel approach to ageing studies assessed the discriminatory ability of a combination of routine physical function tests and novel measures, notably muscle mechanical properties and thigh composition (ultrasound imaging) to classify healthy individuals according to age and gender. The cross-sectional study included 138 community-dwelling, self-reported healthy males and females (65 young, mean age ± SD = 25.7 ± 4.8 years; 73 older, 74.9 ± 5.9 years). Handgrip strength; quadriceps strength; respiratory peak flow; timed up and go; stair climbing time; anterior thigh tissue thickness; muscle stiffness, tone, elasticity (Myoton technology), and self-reported health related quality of life (SF36) were assessed. Stepwise feature selection using cross-validation with linear discriminant analysis was used to classify cases based on criterion variable derived from known effects of age on physical function. A model was trained and features selected using 126 cases with 0.92 accuracy (95% CI...
Background The use of large-scale pooled analyses and data sharing is a potential source to gener... more Background The use of large-scale pooled analyses and data sharing is a potential source to generate evidence to address complex scientific challenges and develop strategies to promote healthy ageing. However, the success of such analyses depends on robust measurements of musculoskeletal (MSK) health in ageing. Simple tests indicative of MSK health and suitable for use with older people are required. This study aims to assess the discriminatory ability of a combination of routine physical function tests and novel measures, notably muscle mechanical properties and ultrasound imaging of thigh composition (relative contribution of muscle and subcutaneous adipose tissue) to classify healthy individuals according to their age and gender. Methods This cross-sectional study included 138 community-dwelling, self-reported healthy males and females (65 young, mean age±SD = 25.7±4.8 years; 73 older, 74.9±5.9 years). Handgrip strength; quadriceps strength; respiratory peak flow; timed up and go...
Objective: To determine the intra-rater reliability of a newly developed movement screening tool;... more Objective: To determine the intra-rater reliability of a newly developed movement screening tool; the ‘Movement control screen for older people in community settings’. The movement screening tool aims to identify movement control impairments which can potentially influence movement function. Method: Thirty one active female recreational golfers, aged 65-77 years, carried out three movement control tests included in the screening tool. Performance was videorecorded to enable repeated ratings. Each test was evaluated by criteria which were rated as pass or fail and ratings were carried out three weeks apart to examine intra-rater reliability. Reliability was assessed using percentage agreement and Cohen’s Kappa. Results: Percentage agreement for each test ranged from 93.0-97.3%, with an overall mean agreement of 95.5%. Kappa values for test scores ranged from 0.35-0.90. Percentage agreement for individual criteria ranged from 83.0-100.0%, with kappa values ranging from 0.00-1.00. Disc...
Introduction: Myotonometry offers an objective, portable, non-invasive way of testing viscoelasti... more Introduction: Myotonometry offers an objective, portable, non-invasive way of testing viscoelastic properties (VP), such as tone and stiffness, of skeletal muscles. The present study examined the differences between VP of healthy young and older males. Methods: Forty-two healthy men were studied; 21 young and 21 older, mean and standard deviation (SD) for age and body mass index were 25.9 (4.4) years, 23.9 (2.5) kg/m2 and 72.1 (4.9) years, 25.2 (3.4) kg/m2 respectively. Participants were tested in supine lying with the leg extended and the muscle in a relaxed state. Viscoelastic properties of rectus femoris (RF)including decrement (elasticity), frequency (tone) and stiffness were measured using the MyotonPro (Muometria AS, Estonia). Damped oscillations of the muscle were recorded in response to a brief (15 milliseconds) mechanical tap applied by the probe with the device held perpendicular to the muscle surface. Two sets of 10 taps were taken and mean of the two used for analysis (t...
Aging clinical and experimental research, Jan 23, 2017
Grip strength is a reliable predictor of whole body strength in older adults, but muscle characte... more Grip strength is a reliable predictor of whole body strength in older adults, but muscle characteristics of people with different activity levels have not been studied previously. The present study examined the relationship between grip strength (GS), quadriceps peak torque (QPT), functional endurance, and health-related quality of life (HRQoL) in older female golfers. Twenty-nine healthy female golfers (mean age 69.1 years, SD 3.4) participated. The ISOCOM and JAMAR dynamometers were used to assess QPT and GS, respectively. Functional endurance tests included 1-min sit-to-stand test (1MSTS), 30-s wall press (30SWP), and 2-min stair climb (2MSC). HRQol was assessed using the SF-36 questionnaire. Mean GS and QPT were 27.5 ± 4 kg/f and 103.7 ± 25.1 N m, respectively. Mean scores for the 1MSTS, 30SWP, and 2MSC were 31 ± 7.7, 17.4 ± 3.5, and 237.5 ± 48.6 repetitions, respectively. GS was moderately correlated with QPT (r = 0.44), 1MSTS (r = 0.36), and 2MSC (r = 0.36), but had weak corre...
Muscle strength may decline with age differentially in the upper and lower limbs. This informatio... more Muscle strength may decline with age differentially in the upper and lower limbs. This information is difficult to capture through a single measure. The present study therefore aimed to characterize the relative changes in handgrip and lower limb muscle strength with aging by expressing them as a ratio. Thirty-eight healthy volunteers aged 20-82 years performed maximal voluntary contractions (MVC) of quadriceps and handgrip using a custom-built transducer and a Jamar dynamometer respectively. The grip-quadriceps ratios for young adults was similar in males and females (0.75); indicating knee extensor force exceeded grip force by approximately 25%. Ratios were increased in older adults (p=0.05), and strength of the two muscle groups was approximately equal (1.1). Pearson's correlation coefficients for grip against quadriceps strength were r=0.63 (young males), r=0.83 (young females), r=0.35 (older males) and r=0.05 (older females). The ratio used demonstrated clear differences between the age groups. The reduced muscle strength with increasing age was expected, but the higher grip/quadriceps strength ratios quantify a greater loss of quadriceps than grip strength with aging. It remains to be investigated whether the relatively greater rate of decline in quadriceps strength seen in healthy older people is more exaggerated in those who are frail, which would have implications for using grip strength as a physical marker of lower limb strength and function in those at risk of immobility and falls.
Background Grip strength is widely used for estimating whole body strength but there is a lack of... more Background Grip strength is widely used for estimating whole body strength but there is a lack of information relating to grip endurance. Comparison between endurance of different muscle groups has received little attention. The main aim of the present study was to determine the endurance characteristics of hand grip and quadriceps muscles in healthy young adults and then to examine the association between fatigability of the two muscle groups. Methods Twenty one healthy participants (8 males and 13 females) aged 18–35 years were studied. A maximal intermittent endurance test, consisting of 12 isometric contractions held for 3 seconds separated by 5 second rest periods, was utilised to measure muscle endurance. A Biodex isokinetic dynamometer and Jamar dynamometer were used to assess quadriceps and hand grip respectively. The mean of first (M1) and last (M2) three repetitions was calculated. Fatigue index values were calculated for both muscle groups by the 1st peak torque (PT) minu...
A novel approach to ageing studies assessed the discriminatory ability of a combination of routin... more A novel approach to ageing studies assessed the discriminatory ability of a combination of routine physical function tests and novel measures, notably muscle mechanical properties and thigh composition (ultrasound imaging) to classify healthy individuals according to age and gender. The cross-sectional study included 138 community-dwelling, self-reported healthy males and females (65 young, mean age ± SD = 25.7 ± 4.8 years; 73 older, 74.9 ± 5.9 years). Handgrip strength; quadriceps strength; respiratory peak flow; timed up and go; stair climbing time; anterior thigh tissue thickness; muscle stiffness, tone, elasticity (Myoton technology), and self-reported health related quality of life (SF36) were assessed. Stepwise feature selection using cross-validation with linear discriminant analysis was used to classify cases based on criterion variable derived from known effects of age on physical function. A model was trained and features selected using 126 cases with 0.92 accuracy (95% CI...
Background The use of large-scale pooled analyses and data sharing is a potential source to gener... more Background The use of large-scale pooled analyses and data sharing is a potential source to generate evidence to address complex scientific challenges and develop strategies to promote healthy ageing. However, the success of such analyses depends on robust measurements of musculoskeletal (MSK) health in ageing. Simple tests indicative of MSK health and suitable for use with older people are required. This study aims to assess the discriminatory ability of a combination of routine physical function tests and novel measures, notably muscle mechanical properties and ultrasound imaging of thigh composition (relative contribution of muscle and subcutaneous adipose tissue) to classify healthy individuals according to their age and gender. Methods This cross-sectional study included 138 community-dwelling, self-reported healthy males and females (65 young, mean age±SD = 25.7±4.8 years; 73 older, 74.9±5.9 years). Handgrip strength; quadriceps strength; respiratory peak flow; timed up and go...
Objective: To determine the intra-rater reliability of a newly developed movement screening tool;... more Objective: To determine the intra-rater reliability of a newly developed movement screening tool; the ‘Movement control screen for older people in community settings’. The movement screening tool aims to identify movement control impairments which can potentially influence movement function. Method: Thirty one active female recreational golfers, aged 65-77 years, carried out three movement control tests included in the screening tool. Performance was videorecorded to enable repeated ratings. Each test was evaluated by criteria which were rated as pass or fail and ratings were carried out three weeks apart to examine intra-rater reliability. Reliability was assessed using percentage agreement and Cohen’s Kappa. Results: Percentage agreement for each test ranged from 93.0-97.3%, with an overall mean agreement of 95.5%. Kappa values for test scores ranged from 0.35-0.90. Percentage agreement for individual criteria ranged from 83.0-100.0%, with kappa values ranging from 0.00-1.00. Disc...
Introduction: Myotonometry offers an objective, portable, non-invasive way of testing viscoelasti... more Introduction: Myotonometry offers an objective, portable, non-invasive way of testing viscoelastic properties (VP), such as tone and stiffness, of skeletal muscles. The present study examined the differences between VP of healthy young and older males. Methods: Forty-two healthy men were studied; 21 young and 21 older, mean and standard deviation (SD) for age and body mass index were 25.9 (4.4) years, 23.9 (2.5) kg/m2 and 72.1 (4.9) years, 25.2 (3.4) kg/m2 respectively. Participants were tested in supine lying with the leg extended and the muscle in a relaxed state. Viscoelastic properties of rectus femoris (RF)including decrement (elasticity), frequency (tone) and stiffness were measured using the MyotonPro (Muometria AS, Estonia). Damped oscillations of the muscle were recorded in response to a brief (15 milliseconds) mechanical tap applied by the probe with the device held perpendicular to the muscle surface. Two sets of 10 taps were taken and mean of the two used for analysis (t...
Aging clinical and experimental research, Jan 23, 2017
Grip strength is a reliable predictor of whole body strength in older adults, but muscle characte... more Grip strength is a reliable predictor of whole body strength in older adults, but muscle characteristics of people with different activity levels have not been studied previously. The present study examined the relationship between grip strength (GS), quadriceps peak torque (QPT), functional endurance, and health-related quality of life (HRQoL) in older female golfers. Twenty-nine healthy female golfers (mean age 69.1 years, SD 3.4) participated. The ISOCOM and JAMAR dynamometers were used to assess QPT and GS, respectively. Functional endurance tests included 1-min sit-to-stand test (1MSTS), 30-s wall press (30SWP), and 2-min stair climb (2MSC). HRQol was assessed using the SF-36 questionnaire. Mean GS and QPT were 27.5 ± 4 kg/f and 103.7 ± 25.1 N m, respectively. Mean scores for the 1MSTS, 30SWP, and 2MSC were 31 ± 7.7, 17.4 ± 3.5, and 237.5 ± 48.6 repetitions, respectively. GS was moderately correlated with QPT (r = 0.44), 1MSTS (r = 0.36), and 2MSC (r = 0.36), but had weak corre...
Muscle strength may decline with age differentially in the upper and lower limbs. This informatio... more Muscle strength may decline with age differentially in the upper and lower limbs. This information is difficult to capture through a single measure. The present study therefore aimed to characterize the relative changes in handgrip and lower limb muscle strength with aging by expressing them as a ratio. Thirty-eight healthy volunteers aged 20-82 years performed maximal voluntary contractions (MVC) of quadriceps and handgrip using a custom-built transducer and a Jamar dynamometer respectively. The grip-quadriceps ratios for young adults was similar in males and females (0.75); indicating knee extensor force exceeded grip force by approximately 25%. Ratios were increased in older adults (p=0.05), and strength of the two muscle groups was approximately equal (1.1). Pearson's correlation coefficients for grip against quadriceps strength were r=0.63 (young males), r=0.83 (young females), r=0.35 (older males) and r=0.05 (older females). The ratio used demonstrated clear differences between the age groups. The reduced muscle strength with increasing age was expected, but the higher grip/quadriceps strength ratios quantify a greater loss of quadriceps than grip strength with aging. It remains to be investigated whether the relatively greater rate of decline in quadriceps strength seen in healthy older people is more exaggerated in those who are frail, which would have implications for using grip strength as a physical marker of lower limb strength and function in those at risk of immobility and falls.
Background Grip strength is widely used for estimating whole body strength but there is a lack of... more Background Grip strength is widely used for estimating whole body strength but there is a lack of information relating to grip endurance. Comparison between endurance of different muscle groups has received little attention. The main aim of the present study was to determine the endurance characteristics of hand grip and quadriceps muscles in healthy young adults and then to examine the association between fatigability of the two muscle groups. Methods Twenty one healthy participants (8 males and 13 females) aged 18–35 years were studied. A maximal intermittent endurance test, consisting of 12 isometric contractions held for 3 seconds separated by 5 second rest periods, was utilised to measure muscle endurance. A Biodex isokinetic dynamometer and Jamar dynamometer were used to assess quadriceps and hand grip respectively. The mean of first (M1) and last (M2) three repetitions was calculated. Fatigue index values were calculated for both muscle groups by the 1st peak torque (PT) minu...
Rapid and unprecedented population ageing poses a serious social and economic challenge across th... more Rapid and unprecedented population ageing poses a serious social and economic challenge across the developed world. Shifts in dependency ratios point to escalating welfare and pensions costs which require radical and imaginative responses from Government and industry. The key to this is maintaining a healthy population that is able and willing to work longer before retirement and can remain independent for as long as possible afterwards as well as bringing disabled people into mainstream life and employment. ontributions focus on the following topics. This chapter focuses on design issues for a more inclusive world, explaining InclusiveCA as a software resource for designers involved in the development and evaluation of truly usable and accessible systems for users with special needs.
International Society for Posture and Gait Research/ Gait and Mental Function 1st joint World Congress, 2012
"Background and Aim:
Turning around to interact with the environment is a common activity of dai... more "Background and Aim:
Turning around to interact with the environment is a common activity of daily living. The location of a target for interaction may be known or unknown prior to turning and the angle of a turn may vary depending on the task to be carried out. A stroke can compromise coordination of body movement during turning] which may pose a risk for instability and subsequent falls. The aim of this study was to investigate the kinematic sequence of rotation of body segments in people with stroke and healthy controls when turning on the spot to predictable and unpredictable targets placed at three different angles (45°, 90° and 135°).
Methods:
Nine people with stroke [age: 64±9 (mean±SD) years] and nine healthy controls [age: 64±9 (mean±SD) years] were asked to stand in front of a light and either turn to a specific light (predictable condition) or locate and turn to a random light (unpredictable condition) placed at 45°, 90° or 135° to the right or left when the light in front extinguished. There were five trials for each task and the tasks were randomized. The onset latency of the horizontal eye movement was measured by an eye camera (VNG Ulmer) and that of the horizontal head, shoulder, pelvis and feet movement were measured by CODA motion.
Results:
There was a top to bottom initiation of rotation of the segments when turning to unpredictable targets and a more simultaneous initiation of the segments when turning to predictable targets in both groups (interaction of segment
and predictability: F=27.004, p=0.001). However, this was not different between the stroke and control groups (Interaction of segment, predictability and group: F=2.887, p=0.082). In the unpredictable condition, there was more simultaneous onset of eye, head and shoulder movement when turning to 45 and 90 degrees as compared to more increasing latencies for the 135 degrees condition (interaction of segment, predictability and angle: F=19.443, p=0.001). There was no difference in the sequence of the segments when turning to both sides in the stroke participants (paretic/non‐paretic sides) and controls (right/left sides) (Interaction of segment, direction and group: F=0.300, p=0.876.
Conclusions:
Predictability of a target affects the sequence of rotation of segments during turning on the spot. The turn angle also affects the sequence when turning to unpredictable targets. The balance of an individual during a task is determined by the movement of the centre of mass within the base of support. This could be affected by the relative movement of the segments involved in the task. The clinical significance of the results of this study may be investigated by relating the sequence of the movement of the body segments to stability during turning. The similarity in the sequence between the groups may be due to motor and sensory deteriorations in the elderly."
Purpose
Objective measurement of mechanical properties of skeletal muscles in a clinical setti... more Purpose
Objective measurement of mechanical properties of skeletal muscles in a clinical setting is difficult. The present study examined inter-rater reliability of a new portable device for objective testing. Relevance Clinical measures of mechanical properties, such as muscle tone, are subjective. An objective tool would enable accurate assessment and monitoring of treatment efficacy.
Participants
Twenty one healthy men aged 20-35 years (mean 25.9, SD 4.4) with body mass index of 23.9 kg/m2 (SD 2.5) were studied.
Methods
Mechanical properties of rectus femoris (RF) and biceps brachii (BB) muscles on the dominant side were tested with the participant in relaxed supine lying. The MyotonPRO device was placed on the relevant muscle belly and applied mechanical taps which induced muscle oscillations, from which frequency (tone; Hz),decrement (elasticity; log), and stiffness (N/m) were measured. Two sets of 10 taps were applied to each muscle (mean of the two used for analysis) by two novice raters.
Analysis
Data were analysed using SPSS 18. Intraclass correlation coefficients (ICC) were used to assess intrarater within session reliability (ICC3,2) and between rater reliability (ICC3,1).
Results
Test-retest reliability for each rater in both muscles was excellent (ICC3,2 0.94-0.99). Inter-rater reliability was excellent for all RF parameters (ICC3,1 decrement 0.95; frequency 0.93; stiffness 0.92) and good to excellent for BB parameters (ICC3,1 decrement 0.78; frequency 0.84; stiffness 0.94).
Conclusions
The MyotonPRO device demonstrated excellent within-session intra-rater reliability and good to excellent inter-rater reliability for RF and BB in asymptomatic young males. Reliability needs to be established between days and for other muscles in healthy and clinical populations. Implications These findings demonstrate that different raters can obtain similar measurements for BB and RF muscles using the MyotonPRO in healthy young males. The device is therefore a potentially valuable tool for objective assessment of muscle in clinical and research settings.
Abstracts for the 8th World Congress on Aging and Physical Activity: A Celebration of Diversity and Inclusion in Active Ageing, 2012
Introduction: Myotonometry offers an objective, portable, non-invasive way of testing viscoelasti... more Introduction: Myotonometry offers an objective, portable, non-invasive way of testing viscoelastic properties (VP), such as tone and stiffness, of skeletal muscles. The present
study examined the differences between VP of healthy young and older males.
Methods: Forty-two healthy men were studied; 21 young and 21 older, mean and standard deviation (SD) for age and body mass index were 25.9 (4.4) years, 23.9 (2.5) kg/m2 and 72.1 (4.9) years, 25.2 (3.4) kg/m2 respectively. Participants were tested in supine lying with the leg extended and the muscle in a relaxed state. Viscoelastic properties of rectus femoris (RF)including decrement (elasticity), frequency (tone) and stiffness were measured using the MyotonPro (Muometria AS, Estonia). Damped oscillations of the muscle were recorded in response to a brief (15 milliseconds) mechanical tap applied by the probe with the device held perpendicular to the muscle surface. Two sets of 10 taps were taken and mean of the two used for analysis (t-tests).
Results: The means and standard deviations for young and older males were: decrement 1.4 (0.2) and 1.8 (0.3), frequency 16.1(1.1) and 16.3 (1.7) Hz, stiffness 288 (22.5) and 322.2 (27.9) N/m respectively. Differences for decrement and stiffness between the groups were statistically significant (p < 0.001) for both.
Conclusions: The MyotonPro enables rapid, objective assessment of viscoelastic properties, suitable for clinical/community settings. Age-related differences between the groups were greater decrement (lower elasticity) and stiffness of RF with ageing. The quadriceps muscles are important for mobility and the MyotonPro is potentially useful as a simple non-invasive device to detect decline in muscle characteristics with ageing and monitor effects of exercise interventions. Further studies of healthy females, other age ranges, and people with different levels of habitual activity are needed to provide reference data for assessing patients.
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Papers by Dinesh Samuel
""
Turning around to interact with the environment is a common activity of daily living. The location of a target for interaction may be known or unknown prior to turning and the angle of a turn may vary depending on the task to be carried out. A stroke can compromise coordination of body movement during turning] which may pose a risk for instability and subsequent falls. The aim of this study was to investigate the kinematic sequence of rotation of body segments in people with stroke and healthy controls when turning on the spot to predictable and unpredictable targets placed at three different angles (45°, 90° and 135°).
Methods:
Nine people with stroke [age: 64±9 (mean±SD) years] and nine healthy controls [age: 64±9 (mean±SD) years] were asked to stand in front of a light and either turn to a specific light (predictable condition) or locate and turn to a random light (unpredictable condition) placed at 45°, 90° or 135° to the right or left when the light in front extinguished. There were five trials for each task and the tasks were randomized. The onset latency of the horizontal eye movement was measured by an eye camera (VNG Ulmer) and that of the horizontal head, shoulder, pelvis and feet movement were measured by CODA motion.
Results:
There was a top to bottom initiation of rotation of the segments when turning to unpredictable targets and a more simultaneous initiation of the segments when turning to predictable targets in both groups (interaction of segment
and predictability: F=27.004, p=0.001). However, this was not different between the stroke and control groups (Interaction of segment, predictability and group: F=2.887, p=0.082). In the unpredictable condition, there was more simultaneous onset of eye, head and shoulder movement when turning to 45 and 90 degrees as compared to more increasing latencies for the 135 degrees condition (interaction of segment, predictability and angle: F=19.443, p=0.001). There was no difference in the sequence of the segments when turning to both sides in the stroke participants (paretic/non‐paretic sides) and controls (right/left sides) (Interaction of segment, direction and group: F=0.300, p=0.876.
Conclusions:
Predictability of a target affects the sequence of rotation of segments during turning on the spot. The turn angle also affects the sequence when turning to unpredictable targets. The balance of an individual during a task is determined by the movement of the centre of mass within the base of support. This could be affected by the relative movement of the segments involved in the task. The clinical significance of the results of this study may be investigated by relating the sequence of the movement of the body segments to stability during turning. The similarity in the sequence between the groups may be due to motor and sensory deteriorations in the elderly."
Objective measurement of mechanical properties of skeletal muscles in a clinical setting is difficult. The present study examined inter-rater reliability of a new portable device for objective testing. Relevance Clinical measures of mechanical properties, such as muscle tone, are subjective. An objective tool would enable accurate assessment and monitoring of treatment efficacy.
Participants
Twenty one healthy men aged 20-35 years (mean 25.9, SD 4.4) with body mass index of 23.9 kg/m2 (SD 2.5) were studied.
Methods
Mechanical properties of rectus femoris (RF) and biceps brachii (BB) muscles on the dominant side were tested with the participant in relaxed supine lying. The MyotonPRO device was placed on the relevant muscle belly and applied mechanical taps which induced muscle oscillations, from which frequency (tone; Hz),decrement (elasticity; log), and stiffness (N/m) were measured. Two sets of 10 taps were applied to each muscle (mean of the two used for analysis) by two novice raters.
Analysis
Data were analysed using SPSS 18. Intraclass correlation coefficients (ICC) were used to assess intrarater within session reliability (ICC3,2) and between rater reliability (ICC3,1).
Results
Test-retest reliability for each rater in both muscles was excellent (ICC3,2 0.94-0.99). Inter-rater reliability was excellent for all RF parameters (ICC3,1 decrement 0.95; frequency 0.93; stiffness 0.92) and good to excellent for BB parameters (ICC3,1 decrement 0.78; frequency 0.84; stiffness 0.94).
Conclusions
The MyotonPRO device demonstrated excellent within-session intra-rater reliability and good to excellent inter-rater reliability for RF and BB in asymptomatic young males. Reliability needs to be established between days and for other muscles in healthy and clinical populations. Implications These findings demonstrate that different raters can obtain similar measurements for BB and RF muscles using the MyotonPRO in healthy young males. The device is therefore a potentially valuable tool for objective assessment of muscle in clinical and research settings.
study examined the differences between VP of healthy young and older males.
Methods: Forty-two healthy men were studied; 21 young and 21 older, mean and standard deviation (SD) for age and body mass index were 25.9 (4.4) years, 23.9 (2.5) kg/m2 and 72.1 (4.9) years, 25.2 (3.4) kg/m2 respectively. Participants were tested in supine lying with the leg extended and the muscle in a relaxed state. Viscoelastic properties of rectus femoris (RF)including decrement (elasticity), frequency (tone) and stiffness were measured using the MyotonPro (Muometria AS, Estonia). Damped oscillations of the muscle were recorded in response to a brief (15 milliseconds) mechanical tap applied by the probe with the device held perpendicular to the muscle surface. Two sets of 10 taps were taken and mean of the two used for analysis (t-tests).
Results: The means and standard deviations for young and older males were: decrement 1.4 (0.2) and 1.8 (0.3), frequency 16.1(1.1) and 16.3 (1.7) Hz, stiffness 288 (22.5) and 322.2 (27.9) N/m respectively. Differences for decrement and stiffness between the groups were statistically significant (p < 0.001) for both.
Conclusions: The MyotonPro enables rapid, objective assessment of viscoelastic properties, suitable for clinical/community settings. Age-related differences between the groups were greater decrement (lower elasticity) and stiffness of RF with ageing. The quadriceps muscles are important for mobility and the MyotonPro is potentially useful as a simple non-invasive device to detect decline in muscle characteristics with ageing and monitor effects of exercise interventions. Further studies of healthy females, other age ranges, and people with different levels of habitual activity are needed to provide reference data for assessing patients.