Quadriceps force generation in patients with osteoarthritis of the knee and asymptomatic participants during patellar tendon reflex reactions: an exploratory cross-sectional study

BACKGROUND: It has been postulated that muscle contraction is slower in patients with osteoarthritis of the knee than asymptomatic individuals, a factor that could theoretically impair joint protection mechanisms. This study investigated whether patients with osteoarthritis of the knee took longer than asymptomatic participants to generate force during reflex quadriceps muscle contraction. This was an exploratory study to inform sample size for future studies. METHODS: An exploratory observational cross sectional study was carried out. Two subject groups were tested, asymptomatic participants (n = 17), mean (SD) 56.7 (8.6) years, and patients with osteoarthritis of the knee, diagnosed by an orthopaedic surgeon, (n = 16), age 65.9 (7.8) years. Patellar tendon reflex responses were elicited from participants and measured with a load cell. Force latency, contraction time, and force of the reflex response were determined from digitally stored data. The Mann-Whitney U test was used for the between group comparisons in these variables. Bland and Altman within-subject standard deviation values were calculated to evaluate the measurement error or precision of force latency and contraction time. RESULTS: No significant differences were found between the groups for force latency (p = 0.47), contraction time (p = 0.91), or force (p = 0.72). The two standard deviation measurement error values for force latency were 27.9 ms for asymptomatic participants and 16.4 ms for OA knee patients. For contraction time, these values were 29.3 ms for asymptomatic participants and 28.1 ms for OA knee patients. Post hoc calculations revealed that the study was adequately powered (80%) to detect a difference between the groups of 30 ms in force latency. However it was inadequately powered (59%) to detect this same difference in contraction time, and 28 participants would be required in each group to reach 80% power. CONCLUSION: Patients with osteoarthritis of the knee do not appear to have compromised temporal parameters or magnitude of force generation during patellar tendon reflex reactions when compared to a group of asymptomatic participants. However, these results suggest that larger studies are carried out to investigate this area further

Postural control is not systematically related to reading skills:implications for the assessment of balance as a risk factor for developmental dyslexia

Impaired postural control has been associated with poor reading skills, as well as with lower performance on measures of attention and motor control variables that frequently co-occur with reading difficulties. Measures of balance and motor control have been incorporated into several screening batteries for developmental dyslexia, but it is unclear whether the relationship between such skills and reading manifests as a behavioural continuum across the range of abilities or is restricted to groups of individuals with specific disorder phenotypes. Here were obtained measures of postural control alongside measures of reading, attention and general cognitive skills in a large sample of young adults (n = 100). Postural control was assessed using centre of pressure (CoP) measurements, obtained over 5 different task conditions. Our results indicate an absence of strong statistical relationships between balance measures with either reading, cognitive or attention measures across the sample as a whole. © 2014 Loras et al

Gross and fine motor function in fibromyalgia and chronic fatigue syndrome

Omid Rasouli,1,2 Egil A Fors,3 Petter Chr Borchgrevink,4,5 Fredrik Öhberg,6 Ann-Katrin Stensdotter1 1Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway; 2Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway; 3Department of Public Health and Nursing, General Practice Research Unit, Norwegian University of Science and Technology, Trondheim, Norway; 4Department of Circulation and Medical Imaging, Pain and Palliation Research Group, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway; 5National Competence Centre for Complex Symptom Disorders, St. Olav’s University Hospital, Trondheim, Norway; 6Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden Purpose: This paper aimed to investigate motor proficiency in fine and gross motor function, with a focus on reaction time (RT) and movement skill, in patients with fibromyalgia (FM) and chronic fatigue syndrome (CFS) compared to healthy controls (HC).Methods: A total of 60 individuals (20 CFS, 20 FM, and 20 HC), age 19–49 years, participated in this study. Gross motor function in the lower extremity was assessed using a RT task during gait initiation in response to an auditory trigger. Fine motor function in the upper extremity was measured during a precision task (the Purdue Pegboard test) where the number of pins inserted within 30 s was counted.Results: No significant differences were found between FM and CFS in any parameters. FM and CFS groups had significantly longer RT than HC in the gait initiation (p=0.001, and p=0.004 respectively). In the Purdue Pegboard test, 20% in the FM group, 15% in the CFS groups, and 0% of HC group, scored below the threshold of the accepted performance. However, there were no significant differences between FM, CFS, and HC in this task (p=0.12).Conclusion: Compared to controls, both CFS and FM groups displayed significantly longer RT in the gait initiation task. Generally, FM patients showed the worst results in both tests, although no group differences were found in fine motor control, according to the Purdue Pegboard test. Keywords: fatigue syndrome, chronic, musculoskeletal diseases, gait initiation, Purdue ­Pegboard, reaction time&nbsp

Início da atividade elétrica dos músculos estabilizadores da patela em indivíduos com SDPF Onset of electrical activity of patellar stabilizer muscles in subjects with patellofemoral pain

OBJETIVO: Avaliar a porcentagem de disparo inicial (PDI) dos músculos estabilizadores da patela durante exercícios de contração isométrica voluntária máxima (CIVM) em indivíduos com e sem sinais da síndrome da dor patelofemural (SDPF) nos exercícios de cadeia cinética aberta (CCA) e fechada (CCF). MÉTODO: Foram avaliadas 10 mulheres sem queixa de dor anterior no joelho e 12 mulheres com sinais de SDPF durante a CIM em CCA e CCF com o joelho posicionado a 90º de flexão do joelho. O início da atividade eletromiográfica dos músculos vasto medial obliquo (VMO), vasto lateral obliquo (VLO) e vasto lateral longo (VLL) foi identificada por meio de um algoritmo no programa Myosystem Br 1. A análise estatística empregada foi o teste Qui-Quadrado e o teste t de student, ambos os teste com nível de significância de 5%. RESULTADOS: Os músculos VMO e VLO apresentaram uma maior PDI em relação ao músculo VLL durante os exercícios em CCA para ambos os grupo e para o grupo SDPF em CCF. Não foi observado diferença entre os grupos. CONCLUSÃO: Pode-se sugerir que tanto os exercícios em CCA quanto em CCF, parecem beneficiar o sincronismo na musculatura estabilizadora da patela, podendo ser indicado nos programas de tratamento fisioterapêutico.<br>OBJECTIVE: To asses the onset (%) of patella stabilizer muscles during maximal isometric contraction exercises (MIC) in individuals with and without signs of patellofemoral pain syndrome (PFPS) in open (OKC) and closed (CKC) kinetic chain exercises. METHOD: Assessments were carried out on 22 women; ten with no complains of anterior knee pain, and 12 with PFPS signs during MIC in OKC and CKC with the knee flexed at 90º. The onset of the electromyographic activity of the vastus mediallis obliquus (VMO), vastus lateralis obliquus (VLO) and vastus lateralis longus (VLL) was identified by means of an algorithm in the Myosystem Br 1 software. The statistical analysis used was Chi-Square test and student's t test, which are both tests with a level of significance at 5%. RESULTS: The VMO and VLO muscles presented a greater onset compared to the VLL during OKC exercises for both groups and for the PFPS group without CCF. No differences were observed between the groups. CONCLUSION: CKC and OKC exercises seem to benefit the synchronism of the musculature that supposedly benefits the patella stabilizer musculature, and can be recommended in physiotherapeutic treatment programs

Atividade eletromiográfica durante exercícios de propriocepção de tornozelo em apoio unipodal Electromyographic activity during ankle proprioception exercises on one-foot stance

Propriocepção refere-se à percepção dos mecanorreceptores para discriminar a posição do corpo e movimentos articulares, bem como tensões sobre os tendões na fase estática ou dinâmica da marcha. Objetivou-se avaliar por eletromiografia a ativação muscular do gastrocnêmio e tibial anterior em diferentes exercícios de propriocepção do tornozelo em apoio unipodal, comparando graus de dificuldade. Foram selecionados 54 voluntários, sedentários, destros, do sexo masculino (20-35 anos). Exercícios foram feitos no balancinho, prancha de equilíbrio, cama elástica e solo, à razão de três repetições de 15 segundos cada, com intervalo de 15 segundos entre as repetições. Ao final dos testes os voluntários indicaram a maior dificuldade. A atividade elétrica de ambos os músculos foi significativamente maior durante o teste no balancinho. No solo, ambos os músculos apresentaram menor atividade, mas apenas no gastrocnêmio essa diferença foi significativa. No exercício na prancha de equilíbrio e na cama elástica não se encontrou diferença quanto à ativação dos músculos. Na análise intermúsculo foi observada maior atividade do tibial anterior, exceto no balancinho. Assim, para o treino do apoio unipodal na aquisição do ganho proprioceptivo, o equipamento adotado deve ser escolhido com cuidado: no balancinho é maior o recrutamento dos músculos tibial anterior e gastrocnêmio, assim como é maior o grau de dificuldade para manutenção do equilíbrio.<br>Proprioception refers to the ability of mechanoreceptors to discriminate body position and joint movements, as well as tensions during static or dynamic phases. The aim of this study was to assess, by means of surface electromyography, activation patterns of the gastrocnemius and tibialis anterior muscles in proprioception exercises, also comparing difficulty levels. Fifty-four sedentary, right-handed, 20-to-35 year-old male volunteers performed single-leg stance exercises on the balance board, wobble board, elastic trampoline and on the floor, at the rate of three 15-second repetitions each, with a 15-second interval between repetitions. After the exercises, volunteers pointed out the highest difficulty felt. Electrical activity of both muscles was significantly higher during the test on the balance board. On the floor, both muscles showed less activity, but only for gastrocnemius muscle this difference was significant. No differences were found in muscle activation during exercises on the wobble board and the elastic trampoline. Inter-muscle analysis showed greater activity of the tibialis anterior muscle, except on the balance board. This study suggests that, when planning one-leg stance exercise for proprioceptive training, the balance board is the equipment that most requires activation of gastrocnemius and tibialis anterior muscles, being also the most difficult one

A statistically compiled test battery for feasible evaluation of knee function after rupture of the Anterior Cruciate Ligament - derived from long-term follow-up data.

PURPOSE: Clinical test batteries for evaluation of knee function after injury to the Anterior Cruciate Ligament (ACL) should be valid and feasible, while reliably capturing the outcome of rehabilitation. There is currently a lack of consensus as to which of the many available assessment tools for knee function that should be included. The present aim was to use a statistical approach to investigate the contribution of frequently used tests to avoid redundancy, and filter them down to a proposed comprehensive and yet feasible test battery for long-term evaluation after ACL injury. METHODS: In total 48 outcome variables related to knee function, all potentially relevant for a long-term follow-up, were included from a cross-sectional study where 70 ACL-injured (17-28 years post injury) individuals were compared to 33 controls. Cluster analysis and logistic regression were used to group variables and identify an optimal test battery, from which a summarized estimator of knee function representing various functional aspects was derived. RESULTS: As expected, several variables were strongly correlated, and the variables also fell into logical clusters with higher within-correlation (max ρ = 0.61) than between clusters (max ρ = 0.19). An extracted test battery with just four variables assessing one-leg balance, isokinetic knee extension strength and hop performance (one-leg hop, side hop) were mathematically combined to an estimator of knee function, which acceptably classified ACL-injured individuals and controls. This estimator, derived from objective measures, correlated significantly with self-reported function, e.g. Lysholm score (ρ = 0.66; p&lt;0.001). CONCLUSIONS: The proposed test battery, based on a solid statistical approach, includes assessments which are all clinically feasible, while also covering complementary aspects of knee function. Similar test batteries could be determined for earlier phases of ACL rehabilitation or to enable longitudinal monitoring. Such developments, established on a well-grounded consensus of measurements, would facilitate comparisons of studies and enable evidence-based rehabilitation

Spatial variation and inconsistency between estimates of onset of muscle activation from EMG and ultrasound.

Delayed onset of muscle activation can be a descriptor of impaired motor control. Activation onset can be estimated from electromyography (EMG)-registered muscle excitation and from ultrasound-registered muscle motion, which enables non-invasive measurements in deep muscles. However, in voluntary activation, EMG- and ultrasound-detected activation onsets may not correspond. To evaluate this, ten healthy men performed isometric elbow flexion at 20% to 70% of their maximal force. Utilising a multi-channel electrode transparent to ultrasound, EMG and M(otion)-mode ultrasound were recorded simultaneously over the biceps brachii muscle. The time intervals between automated and visually estimated activation onsets were correlated with the regional variation of EMG and muscle motion onset, contraction level and speed. Automated and visual onsets indicated variable time intervals between EMG- and motion onset, median (interquartile range) 96 (121) ms and 48 (72) ms, respectively. In 17% (computed analysis) or 23% (visual analysis) of trials, motion onset was detected before local EMG onset. Multi-channel EMG and M-mode ultrasound revealed regional differences in activation onset, which decreased with higher contraction speed (Spearman ??=?0.45, P?&lt;?0.001). In voluntary activation the heterogeneous motor unit recruitment together with immediate motion transmission may explain the high variation of the time intervals between local EMG- and ultrasound-detected activation onset