SUMMARY: Fourteen ambulatory children with spastic diplegia participated in a bilateral quadriceps. strengthening program in an attempt to decrease the amount of knee crouch during gait. Each chid exercised three times a week for six weeks using free ankle weights at a load of 65 per cent of maximum. A normal comparison group of 25 children was also tested under identical conditions. Children with cerebral palsy were significantly weaker in the quadriceps and hamstrings muscle groups than controls. Quadriceps strength increased signficantly at all three angles of knee flexion as a result of the weight‐training program and did not differ statistically from normal at the end of the program. Quadriceps weakness was shown to be a factor in crouch gait; restoring strength through resistance exercise may be a useful adjunct in the treatment of cerebral palsy.RÉSUMÉ: Réponse muscukiire aux exercices á haute résistance chez les enfants présentant tine IMC spastiqueUn programme de renforcement bilatéral des quadriceps a été entrepris cheq 14 jeiines diplégiques spastiques dans une tentative de réduire le niveau de flexion du genou lors de la marche. Un exercice fut appliqué chez chaque enfant, trois fois par semaine durant six semaines utilisant des poids laissant la cheville libre, avec une charge équivalente à 65 pour cent du maximum. Un groupe de comparaison de 25 enfants normaux fut testé dans des conditions identiques. Les enfants IMC avaient une force significativement plus faible que celle des contrôles pout les quadriceps et les ischio‐jambiers. La force du quadriceps s'accrut significativement pour les trois angles de flexion du genou à la suite du programme d'exercice et ne différait plus statistiquement des contrôles à la fin du programme. Ainsi le rôle de la faiblesse du quadriceps dans la flexion du genou durant la démarche sc trouve démontrée; une récupération de force au Iravers d'exercices contre résistance peut étre un apport utile dans le traitement de L'IMC.ZUSAMMENFASSUNG: Muskclantwort atif Krafttruhiing bei Kindern mit spastisclwr CerebralpareseVierzehn ambulante Kinder mit spastischer Diplegie nahmen an einem Trainingsprogramm zur bilateralen Kräftigung des Quadriceps teil, das in dem Versuch gestartet wurde, die Kniebeugestellung beim Gehen zu reduzieren. Jedes Kind trainierte dreimal/Woche insgesamt sechs Wochen lang mit freien Knöchelgewichten mit 65 Prozent der Maximalbelasiung. Eine Vergleichsgruppe von 25 gesunden Kindern urde unter identischen Bedingungen getestet. Die Kinder mit Cerebralparese waren in den Quadriceps‐ und Hamstring‐Muskelgruppen signifikant sehwächer als die Kontrollen. Nach dem Training war die Quadricepskraft in alien drei Winkelstellungen des Kniegelenks so gestärkt, daß sic sich am Ende des Programms statistisch nicht vom Normalen unterschied. Es zeigte Einknicken im Kniegelenk beim Gehen ist; Krafterhaltung durch Training kann ein sinnvolles Hilfsmittel bei der Behandlung der Cerebralparese sein.RESUMEN: Respuesta muscular al ejercicio contra restistenciapesada en niños con parálisis cerebral espásticaCalorce niños ambuhilorios con diplejia espástica parliciparon en un prograinma de tortalecimicnto bilateral del cuadriceps don la idea de disminuir el grado de flexión de rodilla en la marcha. Cada niño hacia ejercicio tres veces por semana durante seis semanas, utilizando a nivel de la rodilla libre pesos de un 65 por ciento del máximo. Un grupo comparativo normal formado por 24 niños realizaron también las pruebas en idénticas condiciones. l.os niños con parálisis cerebral eran significativamcnte más débiles a nivel de cuadriceps y de gemelos que los controles. La potencia del cuádriceps aumcntaba significativamcnte en todos los tres ángulos de flexión de la rodilla como resultado del cntrencmicnto con pesos y no difería del normal cstadisticamente al final del programa. La debilidacl del cuadriceps se vió que era un factor en la marcha agachada. La restauración de la fuerza con ejercicios de resistcncia puede ser una ayuda útil en el tratamiento de la parálisis cerebral.

Background: All the reported measures of sitting posture, as well as photographs, have one flaw, as these measures are external to the body. These measures use calculations from external bony landmarks to estimate spinal posture, on the understanding that what is being measured externally reflects the shape, health and performance of structures of the underlying spine. Without a comparative measure of the relative position of the structures of the spine, the validity of any external spinal posture measure cannot be established. This paper reports on a study which tests the validity of photographs to measure adolescent sitting posture. Methods: The study was conducted in a laboratory at the Department of Human Biology, University of Cape Town. A random sample of 40 adolescents were recruited from the Cape metropolitan schools, to detect differences of three degrees or more between the repeated measures of upright, normal or slouched posture (photographs) and between the posture photographs and LODOX measures. Eligible participants were healthy male and female subjects aged 15 or 16 years old, in Grade 10, and who were undertaking Computer or Computype studies at their schools. Two posture measurement tools were used in the study, namely: Photographs were taken using the Photographic Posture Analysis Method (PPAM) and Radiographs were taken using the LODOX (LODOX (Pty) Ltd) system. Subjects' posture was assessed in simulated computer workstations. The following angles were measured: the sagittal head angle, cervical angle, protraction/retraction angle, arm angle and the thoracic angle. Results: Data from 39 subjects (19 males, 20 females) was used for analysis (17 15-year-olds (7 boys and 10 girls), 22 16-year-olds (12 boys and 10 girls)). All but one photographic angle showed moderate to good correlation with the LODOX angles (Pearson r values 0.67–0.95) with the exception being the shoulder protraction/retraction angle Pearson r values. Bland Altman limits of agreement illustrated a slight bias for all angles. The reliability study findings from repeated photographs demonstrated moderate to good correlation of all angles (ICC values 0.78–0.99). Conclusion: The findings of this study suggest that photographs provide valid and reliable indicators of the position of the underlying spine in sitting. Clinically it is important to know whether a patient is showing true progression in relation to a postural intervention. Based on the results of this study, the PPAM can be used in practice as a valid measure of sitting posture.

Objective: The aim of this study was to investigate the kinetics, kinematics and muscle activity in runners with Achilles tendinopathy. Design: Case–control study. Setting: Biomechanics laboratory. Participants: 21 runners free from injury and 21 runners with Achilles tendinopathy performed 10 running trials with standardised running shoes. Injured runners were diagnosed clinically according to established diagnostic criteria. Uninjured runners had been injury-free for at least 2 years. Main outcome measurements: During each trial, kinetic and lower limb kinematic data were measured using a strain gauge force plate and six infrared cameras respectively. Electromyographic (EMG) data from six muscles (tibialis anterior (TA), peroneus longus (PE), lateral gastrocnemius (LG), rectus femoris (RF), biceps femoris (BF) and gluteus medius (GM)) were measured with a telemetric EMG system. Results: Knee range of motion (heel strike to midstance) was significantly lower in injured runners than in uninjured runners. Similarly, preactivation (integrated EMG (IEMG) in 100 ms before heel strike) of TA was lower for injured runners than uninjured runners. RF and GM IEMG activity 100 ms after heel strike was also lower in the injured group. However, impact forces were not different between the two groups. Conclusion: Altered knee kinematics and reduced muscle activity are associated with Achilles tendinopathy in runners. Rehabilitation exercises or other mechanisms (e.g. footwear) that affect kinematics and muscle activity may therefore be beneficial in the treatment of runners with Achilles tendinopathy.