The efficacy of a 12-week exercise intervention in 11-16 year old adolescents with autism spectrum disorder

Abstract

BACKROUND: Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder, which often results in an array of motor impairments. These motor impairments often lead to reduced performance in activities of daily living (ADLs) as well as in societal tasks which require specific motor abilities and skills. Individuals with ASD have also been reported to have significantly lower physical activity levels compared to typically developing individuals. Motor impairments and these lower physical activity levels have led to various health problems including obesity, cardiovascular disease and insulin resistance syndrome. It may therefore be necessary to intervene in the population, to reduce sedentary-related health risks as well as attempt to improve motor impairments. Since exercise has been shown to be an effective therapeutic modality in reducing motor impairments and improving cardiovascular fitness, the efficacy of exercise interventions within the ASD population needs to be established. OBJECTIVE: To determine the efficacy of a 12 week exercise intervention by assessing the change in posture, body composition, balance, coordination, agility, gait and physical fitness pre- and post-exercise intervention in adolescents with autism aged 11 to 16 years. METHODS: A randomised control trial was conducted to assess the efficacy of an exercise intervention programme in 27 adolescents with ASD (mental age 5.6 ± 1.8 years). The sample was divided into 2 groups (intervention (n=16) and control (n=11)) using randomisation software. Validation of a 12-week exercise intervention was conducted by an expert panel via an online form. The intervention included an aerobic warm up, upper, core and lower body exercises, balance exercises, agility drills, fine motor skill training and a brief aerobic cooldown. All participants were tested pre- and post-intervention, and the intervention group participated in the exercise intervention bi-weekly for 12 weeks, while the control group received their usual standard care. Posture was assessed using a posture grid, and scores out of 10 were given per body area, where good posture = 10, average posture = 5 and poor posture = 0. Body composition, and physical fitness were assessed using the Brockport Physical Fitness Test (BPFT), and balance and coordination were assessed using the MABC-2 test and checklist. Gait was assessed using Dartfish two-dimensional video analysis, and agility was assessed using a standard agility T-test. Data analysis was performed using Stata version 13.1. Descriptive data were expressed as means and standard deviations. To compare variables during pre-and post- intervention within groups for continuous variables, the Wilcoxon signed-rank test was used. To compare variables during pre and post intervention within groups, for categorical variables, Mc Nemar’s test for symmetry was used. Fisher’s exact test was used for categorical variables. Significance was accepted at 95% (p< 0.05). RESULTS: Overall compliance to the intervention was 88.78%; high functioning individuals demonstrated 97.24% compliance, while low functioning individuals demonstrated 77.89% compliance. Posture: there was a significant increase in the overall posture scores (p=0.0004), specifically in the ankle area (p=0.0183) in the intervention group. Cardiovascular fitness: the intervention group showed significant decreases in resting systolic blood pressure (p=0.0069), and systolic blood pressure taken one minute following exercise (p=0.0007). A significant decrease in resting Heart rate (p=0.0046), as well as in heart rate taken one minute following exercise (p=0.0096) was also seen. Anthropometry: although the intervention groups’ weight and body fat percentage did not significantly decrease, there was a significant reduction in BMI (p=0.0130) post intervention. Strength: handgrip strength significantly increased in the non-dominant hand only (p=0.0289), yet there was an overall increase in strength in both hands. The intervention group improved significantly in the amount of curl-ups they were able to perform following the intervention (p=0.0094). Flexibility: for the majority of the flexibility parameters, no significant changes were seen from pre to post testing besides in the intervention group for the sit and reach test for the non-dominant limb (p=0.0088). Manual dexterity: In the MABC-2 test (for age-band 3) there was a significant difference seen in the intervention group (p = 0.200) for the turning pegs item for the non-dominant hand in the intervention group. Coordination: a significant difference was seen in the intervention (p=0.0007) and control group (p=0.0112) for the throwing activity. No conclusive information regarding the efficacy of exercise for this component was however noted. Balance: the intervention group was able to hold their balance for a significantly (p=0.0028) longer time post intervention (17.0 ± 11.0 s) compared to pre intervention (10.5 ± 9.2 s) in the two-board balance task. Agility: there was a significant (p=0.0061) improvement in the agility times from pre (27.4 ± 12.1s) to post (23.0 ± 9.9s) intervention in the intervention group. Gait: there were no significant differences seen following the intervention for all gait parameters. CONCLUSION: A 12 week exercise intervention significantly improved overall posture, cardiovascular fitness, BMI, hamstring flexibility, coordination, balance and agility in individuals with ASD. Handgrip strength and manual dexterity also improved . This therefore suggests that exercise may be a viable therapeutic intervention in the ASD population.