Eur J Pediatr (2009) 168:1327–1333 DOI 10.1007/s00431-009-0930-3
ORIGINAL PAPER
The influence of combined exercise training on indices of obesity, physical fitness and lipid profile in overweight and obese adolescents with mental retardation Sami Mohammed Elmahgoub & Sabine Lambers & Sanne Stegen & Christophe Van Laethem & Dirk Cambier & Patrick Calders
Received: 19 November 2008 / Accepted: 14 January 2009 / Published online: 30 January 2009 # Springer-Verlag 2009
Abstract Introduction This study investigated the effect of combined exercise training on indices of body composition, physical fitness and lipid profile in adolescents with mental retardation. Materials and methods Thirty adolescents with mental retardation (total IQ, 45–70) received exercise training (n= 15) or no training (n=15). Groups were matched for age, sex and mental retardation. Before and after the intervention period, indices of body composition, physical fitness and lipid profile were measured. Results In comparison with the control group, weight, body mass index, waist and fat mass decreased significantly, while relative fat-free mass increased. The level of triglycerides, total cholesterol and low-density lipoprotein decreased significantly, while high-density lipoprotein increased. Muscle strength, muscle fatigue resistance and sit-to-stand were ameliorated. PeakVO2/peak power decreased significantly. The distance covered in the 6-min walk test (6MWT) increased with 50 m. Conclusion In conclusion, combined exercise training has a positive effect on indices of obesity, physical fitness and lipid profile in adolescents with mental retardation. Keywords Combined exercise training . Mental retardation . Body composition . Lipid profile . Physical fitness
S. M. Elmahgoub : S. Lambers : S. Stegen : C. Van Laethem : D. Cambier : P. Calders (*) Rehabilitation Sciences and Physiotherapy Ghent Campus Heymans 1B3, University of Ghent, De Pintelaan 185, 9000 Ghent, Belgium e-mail:
[email protected]
Abbreviations IQ Intelligence quotient BMI Body mass index HR Heart rate 1RM One-repetition maximum FM Fat mass FFM Fat-free mass VO2 Oxygen consumption VCO2 Carbon dioxide production VE Ventilation 6MWT 6-Min walk test 6MWD 6-Min walk distance STS Sit-to-stand test HDL High-density lipoprotein LDL Low-density lipoprotein
Introduction It has been well documented that children, adolescents and adults with mental retardation have sub-optimal levels of cardiovascular fitness compared to persons without mental retardation [15]. The reasons for this impaired fitness are a sedentary lifestyle, associated pathophysiological problems like hypotonia, muscle weakness and an increased prevalence of cardiovascular diseases [9, 18]. The decreased muscle strength, aerobic capacity, fat-free mass and the increased fat mass are associated with a reduced metabolic condition and more specifically with an unfavourable lipid profile [17, 12]. As a consequence, this population has an increased risk for obesity, diabetes and cardiovascular disease. A healthy diet and regular physical activity are key stones in the prevention and treatment of this increased risk
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profile. In children and adolescents without mental retardation, it is proven that physical training has a favourable effect in many ways. Endurance training, strength training and a combination of endurance and strength training have a positive influence on physical and metabolic fitness [4, 5, 8, 19, 25]. However, regarding children with mental retardation, only few data are available. Prior meta-analyses [1, 9] reported that endurance training significantly ameliorated peakVO2, peak ventilation, peak exercise capacity and time to exhaustion. There was no significant effect on body composition and functional capacity. To the best of our knowledge, data about strength training or combination training in children and adolescents with mental retardation are not available. Only a few case studies have been published. In one case study, Lewis and Fragala-Pinkham [14] found a positive effect of combined strength and endurance training. In this study, a 10-year-old child with Down syndrome executed a circuit training including cycling and strength exercise. After the training program, this child had a better submaximal exercise capacity and muscle strength. Body weight did not change. As far as we know, only one publication showed data about the influence of exercise training on metabolic fitness in people with mental retardation. In a study of Varela et al. [23], 16 men (mean age 21.4 years) with Down syndrome were assigned to either an exercise group or a control group. The results showed that aerobic training did not have an influence on oxidative stress in Down syndrome patients. As the potential benefits of combination training for the given risk profile may be important and only data regarding adolescents without mental retardation are available, the purpose of this study was to investigate the influence of combined exercise training on indices of body composition, lipid profile and physical fitness in overweight adolescents with mental retardation.
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done as the initial sample was a homogeneous group with respect to these matching variables. Written consent (signed by parents and adolescents) was obtained from the 30 adolescents (age between 14 and 22 years, body mass index (BMI) between 23 and 48; Fig. 1). Children were diagnosed as fragile X syndrome (eight children) or autism (14 children). The medical record of eight persons did not contain specific information about the cause of mental retardation or associated impairment. Belgium Special Education contains four educational forms. These forms all have other objectives in view of the future of the youngsters [(1) social adaptation = preparing to live in an adapted environment; (2) social adaptation and preparing to function/work in an adapted environment; (3) preparing to function/work in a normal occupational environment; (4) general, occupational, art and technical education]. Within each educational form, students can be recruited from eight different types of education [(1) children with slight mental impairment; (2) children with moderate to severe mental impairment; (3) children with behaviour problems; (4) children with motor impairment; (5) children with long-term sickness; (6) children with visual impairment; (7) children with auditory impairment; and (8) children with severe learning disabilities]. The adolescents participating in this study were recruited from educational form 1, with mainly children with severe mental impairment, and educational form 2, with mainly moderate mental impairment. The measurements of the examined variables were done by blinded assessors. They examined the participants without being aware of the programme followed by each individual. Approval for this study was provided by the ethics committees of the University Hospital Ghent. In Tables 1 and 2, general characteristics of the participants are shown. Eligible for the study: n = 70
Materials and methods Withheld for potential unbiased participation: n = 40
Seventy adolescents with mental retardation (total IQ between 45 and 70) following secondary education from two Special Education Schools (Ravelijn, Brugge and De Einder, Oudenaarde, Belgium) were eligible to participate in the study. In view of evading the potential bias of motivation and ability for regular physical activity in this group, the employed physiotherapists from the institutions were asked to propose a homogenous sample. From the proposed 40 adolescents, a random sample of 15 youngsters was taken to form the interventional group. These participants were matched for age, gender and type of education within the remaining 25 eligible subjects. This could be
Random sampling intervention group: n=15 + Matching control based on age, sex and education form from remaining n=25)
Combined exercise training: n = 15
Control group: n = 15 No drop out
Combined exercise training: n = 15
Fig. 1 Participants’ flow diagram
Control group: n = 15
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Table 1 Influence of combination training on indices of anthropometry and lipid profile Variables
Anthropometry Weight (kg) Length (m) BMI (kg/m2) Waist (cm) Fat mass (kg) Fat-free mass (kg) Fat-free mass (%) Lipid profile Triglycerides (mg/dl) Total cholesterol (mg/dl) HDL (mg/dl) LDL (mg/dl)
Intervention group (n=15)
Control group (n=15)
Pre
Pre
Post
p values Post
75.2 1.67 29.3 92.5 37.0 42.2 53.2
(64.0–139.2) (1.45–1.85) (24.8–48.7) (80–140) (27.9–80.7) (33.2–66.3) (42.1–60.2)
73.8* 1.67 28.1* 90.5* 32.9* 42.8 54.5*
(63.0–136.9) (1.50–1.90) (22.7–47.9) (76–138) (26.4–76.4) (33.8–64.1) (44.2–60.7)
81.6 1.71 27.9 95.0 35.5 45.9 54.2
(52.5–103.8) (1.45–1.92) (23.0–34.3) (82–114) (22.9–52.9) (29.6–54.6) (48.1–63.0)
81.0 1.71 27.7 94.5 35 44.4 52.7
(54.1–105.1) (1.50–1.90) (23.0–32.3) (85–115) (24–50.9) (30.1–54.2) (49.0–62.9)
