Consequences of lower extremity and trunk muscle fatigue on balance and functional tasks in older people: A systematic literature review

<p>Abstract</p> <p>Background</p> <p>Muscle fatigue reduces muscle strength and balance control in young people. It is not clear whether fatigue resistance seen in older persons leads to different effects. In order to understand whether muscle fatigue may increase fall risk in older persons, a systematic literature review aimed to summarize knowledge on the effects of lower extremity and trunk muscle fatigue on balance and functional tasks in older people was performed.</p> <p>Methods</p> <p>Studies were identified with searches of the PUBMED and SCOPUS data bases.</p> <p>Papers describing effects of lower extremity or trunk muscle fatigue protocols on balance or functional tasks in older people were included. Studies were compared with regards to study population characteristics, fatigue protocol, and balance and functional task outcomes.</p> <p>Results</p> <p>Seven out of 266 studies met the inclusion criteria. Primary findings were: fatigue via resistance exercises to lower limb and trunk muscles induces postural instability during quiet standing; induced hip, knee and ankle muscle fatigue impairs functional reach, reduces the speed and power of sit-to-stand repetitions, and produces less stable and more variable walking patterns; effects of age on degree of fatigue and rate of recovery from fatigue are inconsistent across studies, with these disparities likely due to differences in the fatigue protocols, study populations and outcome measures.</p> <p>Conclusion</p> <p>Taken together, the findings suggest that balance and functional task performance are impaired with fatigue. Future studies should assess whether fatigue is related to increased risk of falling and whether exercise interventions may decrease fatigue effects.</p

Testing Gait with Ankle-Foot Orthoses in Children with Cerebral Palsy by Using Functional Mixed-Effects Analysis of Variance

Dr Morrissey is part funded by the NIHR/HEE Senior Clinical Lecturer scheme. Tis report presents independent research part-funded by the National Institute for Health Research (NIHR) CAT SCL-2013-04-00

Muscle Hypertrophy in Prepubescent Tennis Players: A Segmentation MRI Study

PURPOSE: To asses if tennis at prepubertal age elicits the hypertrophy of dominant arm muscles. METHODS: The volume of the muscles of both arms was determined using magnetic resonance imaging (MRI) in 7 male prepubertal tennis players (TP) and 7 non-active control subjects (CG) (mean age 11.0 ± 0.8 years, Tanner 1-2). RESULTS: TP had 13% greater total muscle volume in the dominant than in the contralateral arm. The magnitude of inter-arm asymmetry was greater in TP than in CG (13 vs 3%, P<0.001). The dominant arm of TP was 16% greater than the dominant arm of CG (P<0.01), whilst non-dominant arms had similar total muscle volumes in both groups (P = 0.25), after accounting for height as covariate. In TP, dominant deltoid (11%), forearm supinator (55%) and forearm flexors (21%) and extensors (25%) were hypertrophied compared to the contralateral arm (P<0.05). In CG, the dominant supinator muscle was bigger than its contralateral homonimous (63%, P<0.05). CONCLUSIONS: Tennis at prepubertal age is associated with marked hypertrophy of the dominant arm, leading to a marked level of asymmetry (+13%), much greater than observed in non-active controls (+3%). Therefore, tennis particpation at prepubertal age is associated with increased muscle volumes in dominant compared to the non-dominant arm, likely due to selectively hypertrophy of the loaded muscles

Age- and Gender-Related Changes in Contractile Properties of Non-Atrophied EDL Muscle

Background: In humans, ageing causes skeletal muscles to become atrophied, weak, and easily fatigued. In rodent studies, ageing has been associated with significant muscle atrophy and changes in the contractile properties of the muscles. However, it is not entirely clear whether these changes in contractile properties can occur before there is significant atrophy, and whether males and females are affected differently. Methods and Results: We investigated various contractile properties of whole isolated fast-twitch EDL muscles from adult (2–6 months-old) and aged (12–22 months-old) male and female mice. Atrophy was not present in the aged mice. Compared with adult mice, EDL muscles of aged mice had significantly lower specific force, longer tetanus relaxation times, and lower fatiguability. In the properties of absolute force and muscle relaxation times, females were affected by ageing to a greater extent than males. Additionally, EDL muscles from a separate group of male mice were subjected to eccentric contractions of 15 % strain, and larger force deficits were found in aged than in adult mice. Conclusion: Our findings provide further insight into the muscle atrophy, weakness and fatiguability experienced by the elderly. We have shown that even in the absence of muscle atrophy, there are definite alterations in the physiological properties of whole fast-twitch muscle from ageing mice, and for some of these properties the alterations are mor

Static balance and function in children with cerebral palsy submitted to neuromuscular block and neuromuscular electrical stimulation: Study protocol for prospective, randomized, controlled trial

BACKGROUND: The use of botulinum toxin A (BT-A) for the treatment of lower limb spasticity is common in children with cerebral palsy (CP). Following the administration of BT-A, physical therapy plays a fundamental role in potentiating the functionality of the child. The balance deficit found in children with CP is mainly caused by muscle imbalance (spastic agonist and weak antagonist). Neuromuscular electrical stimulation (NMES) is a promising therapeutic modality for muscle strengthening in this population. The aim of the present study is to describe a protocol for a study aimed at analyzing the effects of NMES on dorsiflexors combined with physical therapy on static and functional balance in children with CP submitted to BT- A. METHODS/DESIGN: Protocol for a prospective, randomized, controlled trial with a blinded evaluator. Eligible participants will be children with cerebral palsy (Levels I, II and III of the Gross Motor Function Classification System) between five and 12 years of age, with independent gait with or without a gait-assistance device. All participants will receive BT-A in the lower limbs (triceps surae). The children will then be randomly allocated for either treatment with motor physical therapy combined with NMES on the tibialis anterior or motor physical therapy alone. The participants will be evaluated on three occasions: 1) one week prior to the administration of BT-A; 2) one week after the administration of BT-A; and 3) four months after the administration of BT-A (end of intervention). Spasticity will be assessed by the Modified Ashworth Scale and Modified Tardieu Scale. Static balance will be assessed using the Medicapteurs Fusyo pressure platform and functional balance will be assessed using the Berg Balance Scale. DISCUSSION: The aim of this protocol study is to describe the methodology of a randomized, controlled, clinical trial comparing the effect of motor physical therapy combined with NMES on the tibialis anterior muscle or motor physical therapy alone on static and functional balance in children with CP submitted to BT-A in the lower limbs. This study describes the background, hypotheses, methodology of the procedures and measurement of the results. TRIAL REGISTRATION: RBR5qzs8

Knee Extension and Flexion Weakness in People With Knee Osteoarthritis: Is Antagonist Cocontraction a Factor?

STUDY DESIGN: Controlled laboratory study, cross-sectional data. OBJECTIVES: To investigate isometric knee flexion and extension strength, failure of voluntary muscle activation, and antagonist cocontraction of subjects with knee osteoarthritis (OA) compared with age-matched asymptomatic control subjects. BACKGROUND: Quadriceps weakness is a common impairment in individuals with knee OA. Disuse atrophy, failure of voluntary muscle activation, and antagonist muscle cocontraction are thought to be possible mechanisms underlying this weakness; but antagonist cocontraction has not been examined during testing requiring maximum voluntary isometric contraction. METHODS: Fifty-four subjects with knee OA (mean ᠓D age, 65.6 ᠷ.6 years) and 27 similarly aged control subjects (age, 64.2 ᠵ.1 years) were recruited for this study. Isometric knee flexion and extension strength were measured, and electromyographic data were recorded, from 7 muscles crossing the knee and used to calculate cocontraction ratios during maximal effort knee flexion and extension trials. The burst superimposition technique was used to measure failure of voluntary activation. RESULTS: Knee extension strength of subjects with knee OA (mean ᠓D, 115.9 ᠶ.7 Nm) was significantly lower than for those in the control group (152.3 ᠹ.6 Nm). No significant between-group difference was found for failure of voluntary muscle activation, or the cocontraction ratios during maximum effort knee flexion or extension. CONCLUSION: These results demonstrate that the reduction in isometric extension strength, measured with a 90ࠫnee flexion angle, in subjects with knee OA is not associated with increased antagonist cocontraction.Full Tex