Effects of resistance training interventions on muscular strength in adults with intellectual disability: a systematic review and meta-analysis

PURPOSE

Muscular strength is critical for adults with an intellectual disability (ID) to promote their mobility, cardiovascular capacity, and performance of daily living/recreational/vocational activities. This article reports the results of the first systematic review and meta-analysis of peer-reviewed clinical trials that evaluated the effects of resistance training (RT) interventions on muscular strength in adults with ID.

METHODS

The protocol was registered with PROSPERO (CRD42020184905). The review focuses on clinical trials that recorded quantitative measures of maximum muscular strength. Eleven electronic databases were searched from their earliest available record up to May 2020. After screening 1996 search records, 11 clinical trials were reviewed.

RESULTS

The RT interventions, while heterogeneous, had an overall significant (p ≤ 0.05) effect on muscular strength in adults with ID, ages 25-58 years. The findings were more significant and less heterogeneous for non-combined RT interventions than for interventions that combined RT exercises with aerobic or balance exercises. The TESTEX overall score was 8.3 ± 3.6.

CONCLUSIONS

RT interventions (particularly when not combined with other exercises) are effective in promoting muscular strength in adults with ID. The limited number of studies and the low study quality scores indicate a potential risk of bias, which limits the interpretation of the findings and warrants further investigation.IMPLICATIONS FOR REHABILITATIONMuscular strength is critical for adults with an intellectual disability (ID) to promote their mobility, cardiovascular capacity, and performance of daily living/recreational/vocational activities.RT interventions are an effective means of improving muscular strength in adults with ID, especially when not combined with other forms of exercise.Testing and assessment protocols used in RT programs should be individualized for adults with ID to accommodate their characteristics and should be implemented under conditions similar to those experienced during the training regimen.It is important to implement familiarization sessions before carrying out muscular strength testing or initiating an RT program to ensure safety, accuracy, and effectiveness of the program for adults with ID.

Intellectual disability, exercise and aging: the IDEA study: study protocol for a randomized controlled trial

BACKGROUND

People with intellectual disabilities (ID) have low levels of physical activity (PA) together with accelerated aging profiles. Adherence to PA interventions for persons with ID is low based on barriers such as motivation. The IDEA study aims to determine the effect of two types of exercise programs, continuous aerobic (CAEP) vs sprint interval training (SIT), designed for seniors with ID on health-related physical fitness, cardiovascular parameters, quality of life (QoL), and emotional and cognitive function.

METHODS

In this trial, ninety seniors with ID between the ages of 40 and 75 yrs. from occupational health centers from the Autonomous Region of Catalonia (Spain) will be recruited. Participants will be randomly allocated to the CAEP, SIT, and control group. Both intervention groups will train 3 days/week, 1.5 h/day over 6 months. Outcome variables will be assessed at baseline, 6 months and 12 months. The outcome variables include weight, height, body composition, cardiorespiratory fitness, muscle strength, balance, flexibility, cardiovascular parameters (blood pressure, pulse-wave velocity, pulse-wave analysis), QoL and cognitive function. The intervention effect will be determined with mixed models with repeated measures to assess changes in the outcome variables over time (baseline to month 12) and between study arms. Relationship between variables will be analyzed with appropriate regression analyses.

DISCUSSION

Various studies reported on CAEP and SIT as exercise interventions for persons with ID with beneficial outcomes on body composition, fitness and blood pressure. To our knowledge, this is the first trial designed to analyse the positive changes on fitness, PA levels, cardiovascular, QoL and cognitive function promoted by CAEP training and SIT in seniors with ID. The findings of this study will assist in the development of more effective exercise interventions to ensure better compliance and adherence to exercise in seniors with ID.

TRIAL REGISTRATION

The trial is registered at the ISRCTN registry. Registration number: ISRCTN43594228 . Registered 11 February 2019 - Retrospectively registered.

Neuromuscular characteristics in trained vs. sedentary male adults with intellectual disability

BACKGROUND

This study aimed to explore muscle strength production and its underlying neuromuscular characteristics in sedentary and trained individuals with intellectual disability (ID) compared with healthy sedentary individuals.

METHODS

Three adult groups (age: 25.07 ± 0.70) consisting of sedentary individuals with ID (IDSG), trained individuals with ID (IDTG) and a control group (CONT) participated in the present study. Peak torque (PT) during maximal voluntary isometric contraction, voluntary activation level (VAL), surface electromyography (sEMG) recordings, electrophysiological (M_max ) and potentiated twitch torque (PTT responses) of the knee extensor muscles and thigh muscle volume were assessed.

RESULTS

Compared with CONT and IDTG, respectively, IDSG presented significantly lower PT (-48% and -42%), VAL (-24% and -9%), sEMG (-49% and -29%), M_max (-41% and -39%) and PTT (-32% and -28%) values. These deficits were reduced between IDTG compared with CONT (i.e. PT: -10%; VAL: -16%; and sEMG: -28%) or did not differ anymore (PTT and M_max ). Normalising PT to thigh muscle volume and/or computing theoretical PT value overwhelm strength production differences between IDTG and CONT. Training background influences the outcomes with IDTG exhibiting greater PT, VAL, sEMG, M_max and PTT than IDSG.

CONCLUSIONS

Strength production deficit in IDSG was related to both muscular and neural characteristics compared with healthy controls whereas this deficit mainly arises from neural characteristics for IDTG.

Effects of exercise on the physical fitness level of adults with intellectual disability: a systematic review

Purpose: To systematically review the existing scientific evidence regarding the effects of physical exercise on the fitness level of people with intellectual disabilities.Methods: Following the checklist of the Preferred Reporting Items for Systematic review and Meta-Analysis Protocols, the PubMed, CINAHL, SPORTDiscus, and Scopus databases were searched using specific keywords up to January 2018. The methodological quality of the studies found was rated by the means of specific scales according to their specific design.Results: A total of 44 studies were selected. The majority of the included studies were randomized controlled trials (n = 17), followed by non-controlled studies (n = 11), non-randomized controlled trials (n = 10), and comparative studies (n = 6). Aerobic, strengthening, and combined exercise programs were the most frequently proposed interventions. Exercise showed to have significant effects on the cardiorespiratory and muscular fitness. Not all the selected studies reported improvements in parameters related to body composition.Conclusions: There is sufficient scientific evidence for the beneficial effects of exercise on the cardiovascular and muscular fitness of adults with mild/moderate ID. There is a need for more studies focused on the impact of physical exercise on the body composition of this population, and those that aim at identifying the impact of alternative interventions.IMPLICATIONS FOR REHABILITATIONThere is a need for basic guidelines that can help rehabilitation professionals to prescribe exercise for maintaining and improving physical fitness in the adults with intellectual disabilities.In adults with intellectual disabilities, aerobic exercise has beneficial effects on cardiovascular and muscular fitness, flexibility, and range of motion.No firm conclusion can be made regarding the effects of aerobic, muscular, and combined training programs on the body composition of adults with intellectual disabilities.Rehabilitation professionals should be aware that scientific evidence regarding the prescription of alternative exercise protocols in adults with intellectual disabilities (i.e. dancing, water-based exercise, animal therapy, etc) is scarce.

Physical Activity Research in Intellectual Disability: A Scoping Review Using the Behavioral Epidemiological Framework

Through a scoping review, the current state of physical activity research in people with intellectual disability was examined. A search of publications between 2000 and 2014 retrieved 362 articles that met inclusion criteria. Eligible studies were coded according to the Behavioral Epidemiological Framework. Of the articles identified, 48% examined associations between physical activity and health outcomes, 9% developed or tested methodology to measure physical activity, 34% examined factors that influence physical activity, 8% evaluated interventions to change physical activity, and 1% examined the dissemination of physical activity/health promotion programming. The categories with lower proportions of studies represent the need for greater population-specific research in physical activity measurement, interventional designs, and translational programs.

Development of a new index of balance in adults with intellectual and developmental disabilities

PURPOSES

The first objective was to propose a new model representing the balance level of adults with intellectual and developmental disabilities (IDD) using Principal Components Analysis (PCA); and the second objective was to use the results from the PCA recorded by regression method to construct and validate summative scales of the standardized values of the index, which may be useful to facilitate a balance assessment in adults with IDD.

METHODS

A total of 801 individuals with IDD (509 males) mean 33.1 ± 8.5 years old, were recruited from Special Olympic Games in Spain 2009 to 2012. The participants performed the following tests: the timed-stand test, the single leg stance test with open and closed eyes, the Functional Reach Test, the Expanded Timed-Get-up-and-Go Test. Data was analyzed using principal components analysis (PCA) with Oblimin rotation and Kaiser normalization. We examined the construct validity of our proposed two-factor model underlying balance for adults with IDD. The scores from PCA were recorded by regression method and were standardized.

RESULTS

The Component Plot and Rotated Space indicated that a two-factor solution (Dynamic and Static Balance components) was optimal. The PCA with direct Oblimin rotation revealed a satisfactory percentage of total variance explained by the two factors: 51.6 and 21.4%, respectively. The median score standardized for component dynamic and static of the balance index for adults with IDD is shown how references values.

CONCLUSIONS

Our study may lead to improvements in the understanding and assessment of balance in adults with IDD. First, it confirms that a two-factor model may underlie the balance construct, and second, it provides an index that may be useful for identifying the balance level for adults with IDD.

Resistance circuit training reduced inflammatory cytokines in a cohort of male adults with Down syndrome

BACKGROUND

It is widely accepted that muscle strength plays a key role on functional tasks of daily living and employability in individuals with Down syndrome (DS). Recent studies have also reported resistance training may improve chronic inflammation in other clinical situations. This is the first study conducted to determine the effect of resistance circuit training on low-grade systemic inflammation in adults with DS.

MATERIAL/METHODS

A total of 40 young male adults with DS were recruited for the trial through different community support groups for people with intellectual disabilities and their families. They had medical approval for physical activity participation. Twenty-four were randomly assigned to perform resistance circuit training with 6 stations, 3 days per week for 12 weeks. Exercise intensity was based on function of the 8RM assessments. The control group included 16 age-, sex-, and BMI-matched adults with Down syndrome. Plasma levels of leptin, adiponectin, and TNF-a were assessed by commercial ELISA kits. C-reactive protein (CRP) was assessed by nephelometry. Body composition was also determined, measuring fat-free mass percentage and waist circumference (WC). This protocol was approved by our Institutional Ethics Committee.

RESULTS

Plasma levels of leptin, TNF-a, and IL-6 were significantly decreased after the completion of the training program, as were fat-free mass and WC. No sports-related injuries or withdrawals from the program were reported during the entire study period. No changes were observed in the control group.

CONCLUSIONS

Resistance circuit training improved low-grade systemic inflammation in male sedentary adults with DS.

Differences in muscle activation patterns during sit to stand task among subjects with and without intellectual disability

The aim of this study is to analyse the differences in muscle activity between subjects who have intellectual disability and healthy subjects when they make the transition from sitting to standing positions. A cross-sectional study. A group of adults was divided into two subgroups: with and without intellectual disability (ID). The means of the basic features in both groups were 22.13 and 22.83 for age, 66.38 and 67.67 for weight, and 173.38 and 174.33 for height, for the ID (n = 8) and without ID (n = 7) groups, respectively. Each subject performed three sets of five repetitions during which, starting from sitting, they had to get up and sit on the chair. The recording of muscle activity was performed using surface electromyography taking the measures of muscle activity of different muscles of the lower limbs. The results showed differences in the pattern of muscle activity between groups during sitting to standing movement.

Effect of a hippotherapy intervention program on static balance and strength in adolescents with intellectual disabilities

The aim of this study was to assess the effects of a hippotherapy program on static balance and strength in adolescents with intellectual disability (ID). Nineteen adolescents with moderate ID were assigned either an experimental group (n=10) or a control group (n=9). The experimental group attended a 10-week hippotherapy program. To assess static balance, three tasks of increasing difficulty (Double-Leg Stance with opened or closed eyes, and One-Leg Stance with opened eyes) were performed while standing on an EPS pressure platform (Loran Engineering S.r.I., Bologna, Italy). The strength measurements consisted of three maximal isometric half-squats from the seating position (knee joint at 90°). The hippotherapy intervention program resulted in significant improvements in strength parameters, and on the more complex balance task (i.e. standing on one leg). In conclusion, this study provides evidence that hippotherapy can be used as an effective intervention for improving balance and strength in individuals with ID, and could thus influence functional activities and quality of life.

Basketball ability testing and category for players with mental retardation: 8-month training effect

Although sport for athletes with mental retardation (MR) is achieving an important role, the literature concerning basketball tests and training is still poor. The aims of this study were to verify whether the basketball test battery could be an appropriate modality to classify the players in the Promotion (Pro) category, to assess basketball abilities before (PRE) and after (POST) an 8-month training in players with MR in relation to Competitive (Comp) and Pro categories, to analyze the variation of specific basketball abilities based on subjects' MR diagnosis. Forty-one male basketball players with MR (17 Comp and 24 Pro; age range 18-45 years; MR: 15% mild, 54% moderate, 29% severe, and 2% profound) were assessed PRE and POST training through the basketball test battery, which assessed 4 ability levels of increasing difficulty (from I to IV), each one characterized by the analysis of fundamental areas (ball handling, reception, passing, and shooting). Level I was significantly changed after the intervention period regardless of the Category, whereas shooting was affected by the interaction between Category and Intervention. The results showed significant differences between categories in the scores of individual global, level I, level II, level III, and in all fundamental areas. Individual global score in both categories significantly increased. The players of Comp significantly improved in level III, in ball handling, reception, passing, and shooting scores. The players of Pro improved significantly in level II, in ball handling, reception, and passing scores. Individual global, ability levels I-III, and fundamental area scores were negatively correlated to the MR level indicating that the players with a lower MR obtained higher ability scores. In conclusion, it was found that the basketball test battery could be useful for improving and monitoring training in both Comp and Pro players.

The effect of combined exercise training in adolescents who are overweight or obese with intellectual disability: the role of training frequency

Data about effects of exercise training in adolescents with intellectual disability (ID) are very limited. This study investigated the effect of 2 different frequencies of the same intensity and total training volume of combined exercise training on indices of body composition, physical fitness, and lipid profile in overweight and obese adolescents with ID. A total of 45 overweight and obese adolescents with ID aged 14-22 years with a total IQ 45-70 received combined exercise training 3 times a week (CET3) for 30 sessions (10 weeks; n = 15), twice a week (CET2) for 30 sessions (15 weeks; n = 15), or no training (10 weeks; n = 15). Groups were matched for age, sex, and education form. Before and after the intervention period, indices of body composition, physical fitness and lipid profile have been evaluated. Compared to the control group, CET3 resulted in a significant improvement of physical fitness, obesity indices, and lipid profile of the participants. Comparing CET2 with CET3, no significantly different evolutions were noticed, except for lower limb strength in favor of exercising 3 times a week. In conclusion, exercising 2 times a week, which is more feasible and practical for participants and guidance, has the same health beneficial effects as 3 times per week in overweight and obese adolescents with ID in short-term training.