Chapter 4 The Effects of Aquatic Intervention on Energy Expenditure and Gross Motor Function in Children with Cerebral Palsy

Transcription

1 The Effects of Aquatic Intervention on Energy Expenditure and Gross Motor Function in Children with Cerebral Palsy Getz, M., Hutzler, Y., Vermeer, A., & Yarom, Y. (2006). Manuscript submitted for publication.

2 Abstract Purpose: The aim of this study was to compare the effects of aquatic intervention with those of land-based intervention on energy expenditure and gross motor function in children with cerebral palsy (CP). Seventeen children with spastic diplegia CP participated in the study: 9 in the aquatic intervention group (5.3 yr ) and 8 in the exercise intervention group (4.7 yr +.95) (3 children from the exercise group were excluded because of medical and participation limitations, leaving 5). Energy expenditure was measured by expired gas and velocity of walking using the Cosmed K4b 2 metabolic system and the energy expenditure index. Self-paced and fast ground walking speed were measured by the 10-meter walk. Gross motor performance was measured by the Gross Motor Function Measure (GMFM) and Pediatric Evaluation of Disability Inventory (PEDI). Repeated measure analyses of variance and effect sizes were carried out and calculated for each dependent variable before and after a four-month intervention period. Results: No significant differences were found between groups in energy expenditure measures. However, group effect sizes and mean trends suggested a more favorable decrease in energy expenditure in the aquatic intervention group than in the exercise intervention group. Effect sizes of the 10-meter walk were larger in the exercise group than in the aquatic intervention group. No significant differences were found between groups on the GMFM measure. The aquatic intervention group improved significantly (p<0.05) in the PEDI mobility domain, and no significant differences were found in the PEDI selfcare domain. Conclusions: Aquatic intervention may be more favorable for improving the energy cost of walking and prolonged non-specific weight bearing activities in children with spastic diplegia CP. Exercise intervention seems to be more favorable in improving functional performance in short-term tasks requiring exact coordination for weight bearing activities. It is recommended to combine both means of intervention to increase functional levels in this population. 70

3 The Effects of Aquatic Intervention on Energy Expenditure Introduction Cerebral palsy is defined as a non-progressive insult to a developing or immature central nervous system, particularly to areas that affect motor function (Gage, 1991). Children with cerebral palsy (CP) typically experience difficulty in developing normal movement patterns. The motor impairment affects the development of motor skills and causes inappropriate compensatory movement patterns that further impede development. Children with CP exhibit a variety of primary and secondary deficiencies. Exaggerated muscle tone is present in 75% of all cases and interferes with the execution of controlled isolated movements (Katz & Rymer, 1989; Lehman, Price, delateur, Hinder, & Traynor, 1989; Parker, Carrire, Hebestreit, Salsburg, & Bar-Or, 1993). Thus, the children s ability to walk is of primary concern to their parents, and improving or attaining this ability is frequently the main focus of therapeutic interventions (Bleck, 1990). Past research has indicated that children with physical disabilities expend more energy during walking than able-bodied children (Duffy, Hill, Cosgrove, Corry, & Graham, 1996; Johnston, Moore, Quinn, & Smith, 2004). Furthermore, they have demonstrated decreased walking proficiency and a higher than normal oxygen uptake (VO 2 ) during walking (Campbell & Ball, 1978; Duffy et al., 1996; Maltais, Bar-Or, Galea, & Pierrynowski, 2000; Unnithan, Dowling, Frost, & Bar-Or, 1996). Duffy et al. (1996) found that children with spastic diplegia showed a significantly higher heart rate during walking than children with spastic hemiplegia and spina bifida, suggesting that the level of disability can affect the energy cost of walking. Johnston et al. (2004) found a strong relation (r=.87, p<.01) between the energy cost of walking and gross motor function in children with cerebral palsy. Increased VO 2 may be the main contributor to fatigue in this population. If this higher energy consumption is not decreased, children may be expected to reduce their participation in locomotor activities, further increasing their body weight and fat percentage, which in turn further limits their activity rate (Longmuir & Bar-Or, 2000). Previous studies have found a relation between muscle weakness and motor function in children with CP (Damiano, Martellotta, Sullivan, Granata, & Abel, 2000; Damiano & Abel, 1996; Whiley & Damiano, 1998). In addition, a strong relationship has been demonstrated between spatio-temporal walking parameters and performance scores on the Gross 71

4 Motor Function Measure (GMFM) in children with CP (Damiano & Abel, 1996; Drouin, Malouin, Richards, & Marcoux, 1996). Based on these studies, it can be surmised that the high VO 2 consumption during walking and other motor activities in children with CP is attributable to the combination of weak muscle strength and inefficient movement patterns due to pathological muscle tone. It has been suggested that swimming and aquatic therapy are among the more beneficial activities for children with motor deficiencies (Adams & McCubbin, 1991; Christie, 1985; Harris, 1978). Therapeutic interventions in an aquatic environment provide unique benefits and movement opportunities that are difficult to accomplish on land. The specific benefits of the aquatic environment have been reported elsewhere (Becker & Cole, 2004; Getz, Hutzler, & Vermeer, 2006) Although based on limited scientific evidence, it is commonly conceived that exercising in an aquatic environment can improve muscle strength and endurance in children with CP (Becker & Cole, 2004; Broach & Datillo, 1996). Svedenhag & Seger (1992) have found that while running in water (wearing a life vest) different movement patterns were generated and a larger muscle mass was activated than during treadmill running. Furthermore, energy consumption during running in water is significantly lower than during land treadmill running (Christie et al., 1990). This suggests that a child with CP could engage in physical activity longer in an aquatic environment, conditioning more muscle groups, before reaching fatigue. Evidence from other participant groups follows. Gehlsen, Grisby, & Winant (1984) found that aquatic exercise improved muscular strength and power and decreased fatigue of knee extensor muscles in participants with Multiple Sclerosis (MS). Peterson (2001) found in a case report involving a patient with MS that major motor milestones such as walking, were attained in the aquatic environment before they were attained on land. Additionally, achieving independent walking ability in the aquatic environment, without the use of assistive devices, appeared to be an important motivating factor for this participant. However, because of the restriction of the study design, the author was not able to conclude whether functional training in the aquatic environment had a direct effect on performance in land activities. Despite the popularity of aquatic activity as a therapeutic means in children with CP and its potential to improve physiological and motor performance, little 72

5 The Effects of Aquatic Intervention on Energy Expenditure research has been conducted thus far to measure specific outcome effects. The purpose of this study was to determine (1) the effects of an aquatic intervention program on measured and predicted energy expenditure during walking on land, and (2) to establish the effects of aquatic intervention on gross motor function in children with CP. Method A controlled group design was used, with an experimental group participating in an aquatic intervention program and a control group participating in a landbased exercise program. Participants Seventeen children (12 females and 5 males) with cerebral palsy (spastic diplegia), aged 3-6 participated in the study (Table 1). All children met the following criteria: (1) medical diagnosis of CP of the spastic diplegia type; (2) no other medical complications such as seizures; (3) normal intelligence and ability to comprehend instructions; (4) special education setting supervised by the Israeli Ministry of Education; (5) no medical procedures involving the lower limbs performed in the preceding 12 months (including casting and botulinum toxin injections); (6) ability to walk three minutes at a selfpaced speed; (7) functional performance level between I-III on the GMFCS (Palisano et al., 1997); (8) written parental approval. The study was approved by the scientific committee of the Ministry of Education and by the Helsinky ethics committee for approving research in human subjects of the Chaim Sheba Medical Center, Israel. 73

6 Table 1. Distribution of Participants According to Gender, Age, and Level of Activity Across Groups Characteristics Aquatic Intervention Exercise Intervention Age ( y:m) Gender GMFCS Mean (SD) 5:3 (1.02) 4:7 (.95) Male 4 1 Female 5 7 I 1 II 1 2 III 8 5 Instruments Energy Expenditure in Walking. Gait criteria of children participating in the study were assessed by a 10-meter walking test (Damiano, Mark & Abel, 1998), energy expenditure index (Rose & Gambel, 1991), and direct metabolic measurement using the Cosmed K4b 2 system. This is a portable breath-by-breath metabolic measuring and recording system. The K4 b 2 uses a facemask with a turbine flow-meter and oxygen electrode. The child uses a special harness to carry a gas sampler, telemetry transmitter, and battery pack with a total weight of about 600g. A receiver and data processing system are carried by a technician. The K4 b 2 has been validated and found reliable (Dufield, Dawson, Pinnington, & Wong, 2004), and has been used with children with and without disabilities (Littlewood, Davies, Cleghorn, & Grote, 2004). The system is favored mainly because it enables children to be tested while walking freely on the floor, using their own locomotor aids, rather than on a treadmill, where training and habituation are required (Duffy, et al. 1996). In earlier trials of the one minute walk we found that heart rate (HR) values dropped substantially, in some cases to resting values, if the child was 74

7 The Effects of Aquatic Intervention on Energy Expenditure required to execute turns during walking rather than walk in a straight line. Therefore, to obtain reliable energy cost values, we asked the child to walk on a straight terrain that did not require changes in walking directions. The longest distance present in our gymnasiums was 34 meters. The metabolic measurement procedure was similar to the Energy Expenditure Index protocol, with some adaptations that were required because it was clear when a child reached steady state values. Therefore, the amount of time it took a child to reach steady state values differed according to the child s level of ability. All children walked the distance of 34 meters, regardless of the time they required. Each child was equipped with a Polar S610 heart rate monitor. The metabolic apparatus was fitted next. After children indicated that they were comfortable wearing the mask, they were asked to sit for a period of three minutes or until predictive resting values of HR were observed. The children were then asked to walk at a self-paced speed, with shoes and walking aids, until steady state values were observed. Then children were asked to walk a diagonal line of 34 meters without stopping, after which they were seated until HR values reached resting values. The energy cost of walking (ml * kg -1 *min -1 ) was calculated by dividing the energy consumption (ml O 2 *kg -1 *min -1 ) by the velocity (time it took to travel 34 meters (m * min -1 )). A certified exercise physiologist lab technician administered the test with the aid of two adapted activity professionals. Energy Expenditure Index (EEI). Predicted energy expenditure was calculated by extracting the steady state resting HR from the steady state walking HR divided by the walking velocity (Rose, Gamble, Burgos, Medeiros, & Haskell, 1990; Rose & Gambel, 1991). The EEI has been employed in differentiating between energy needs of different populations (Duffy et al., 1996) and detecting changes following clinical (Damiano et al., 1998) and therapeutic interventions (McGibbon et al., 1998). The EEI protocol was as follows: (1) the child was equipped with a Polar S610 heart rate monitor; (2) the child was asked to sit quietly for a period of five minutes, and the recorded HR for the last two minutes was averaged to determine the resting HR (Maltias et al., 2000); (3) the child was asked to walk with shoes at a self- paced speed for three minutes, and the last minute HR was recorded to ensure the child reached a steady state (Damiano et al., 1998) (we reduced the time for reaching steady state values to three minutes because 75

8 in earlier trials we found that most of the children were not able to walk for a longer period of time); (4) after the three minutes, the child was asked to walk along a 34-meter diagonal line to determine the metabolic and spatiotemporal variables used to calculate energy expenditure. Time, averaged HR, and number of steps were recorded. If the child did not complete the 34-meter distance in one minute, the distance and number of steps were recorded for this period of time (Damiano et al., 1998). Energy expenditure was calculated by subtracting resting HR (b * min -1 ) values from exercise HR values divided by the velocity of walking (m * min -1 ). Two adapted activity professionals administered the test. 10 meter walk. Children were given a practice walk during which no data were recorded in order to familiarize them with the procedure. Children were then asked to walk a 14-meter distance under two conditions, each condition prompted by a verbal cue: (1) Walk as fast as you can without running, and (2) Walk at your regular speed. An observer used a stopwatch to measure the time it took the child to walk the 10-meter distance from the time the first foot touched the starting line and until the last foot contacted the end of the 10-meter line. Time was recorded for each trial. Children performed three trials under each condition and rested between trials until HR was within 10% of resting values (Maltias et al., 2000). Velocity (m * sec -1 ) was calculated by dividing the mean time values it took the child to walk 10 meters under each condition. Gross Motor Function Measure (GMFM). Physiotherapists in each kindergarten administered the 66-item version of GMFM. Before the first evaluation, physiotherapists attended a GMFM training session supported by the Ministry of Education in Israel. GMFM (Russell, Rosenbaum, Avery, & Lane, 2002) is a standardized observational instrument for children with CP and head trauma designed to measure change over time. It has been shown to be reliable and valid (Rosenbaum et al., 1990; Russell, Rosenbaum, & Cuadman, 1989) and has been used to detect change in motor function following clinical (Nordmark, Jarnlo, & Hagglund, 2000) and therapeutic interventions (Ketelaar et al., 2001; Trahan & Malaouin, 2002). The 66-item version of GMFM was administered to all participants in the five dimensions: A (lying and rolling), B (sitting), C (crawling and kneeling), D (standing), and 76

9 The Effects of Aquatic Intervention on Energy Expenditure E (walking, running, and jumping). Scores on each dimension and the total tests were obtained with the Gross Motor Ability Estimator (GMAE). GMAE is a computer program used to analyze scores on the 66-item GMFM (Russell, Rosenbaum, Avery, & Lane, 2002). Pediatric Evaluation of Disability Inventory (PEDI). The PEDI (Hayley, Coster, Ludlow, Haltiwanger, & Andrellos, 1992) was administered by a trained adapted physical activity professional. This is a standardized instrument for evaluating functional performance through a structured interview with caregivers and therapists. It has been shown to be reliable and valid (Feldman et al., 1990; Hayely et al., 1991; Nickolas & Case Smith, 1996), and to discriminate between children with no disabilities and children with CP (Ketelaar & Vermeer,1998). PEDI has been proven efficient in documenting changes in function after medical interventions (Normak et al., 2000) and treatment-based interventions (Ketelaar et al., 2001) in children with CP or related neurological impairments. The PEDI is divided into three domains: (1) self care, (2) mobility, and (3) social function. The mobility and self-care domains were administered. Aquatic assessment. A slightly modified version of the Water Orientation Scale (Hutzler et al., 1998), relabeled as the Aquatic Independence Measure (AIM) was used to assess the children s level of skill acquisition in the aquatic environment. AIM was developed in Israel and designed specifically to assess aquatic performance in children with motor deficiencies. Recent evaluation found high inter-rater and intra-rater reliability of the instrument (ICC>.99) (Chacham & Hutzler, 2001). Procedure Children in the study group participated in an ongoing adapted aquatics program conducted in two kindergartens for children with physical disabilities. Children in the control groups were placed in a different kindergarten for children with physical disabilities who did not participate in adapted aquatic sessions as part of their educational curriculum. Pre-test measures were recorded after a minimum of three months attendance in the different programs to ensure habituation to the intervention settings and to the staff. Post-test measures were recorded after a four-month period during which 32 77

10 sessions were held in each group. Measures were recorded in a random order over a three-week period. Post-test measures of three children from the initial exercise group (n=8) were not collected because of medical conditions and attendance (n=1 seizure attacks; n=1 botulinum toxin injections; n=1 attended only 30% of sessions). Thus the final sample was five children in the exercise group and nine children in the aquatic intervention group. Aquatic Intervention The adapted aquatics program consisted of two weekly, individualized, 30- minute sessions. Each child was assigned to a trained instructor throughout the program. Goals were individually determined to meet the specific needs of each participant in cooperation with the attending physiotherapist. A multidisciplinary approach was used to determine program goals and objectives with an emphasis on improving functional abilities in a water environment with reference to the AIM (Chacham & Hutzler, 2001) and to the 10-point program of the Halliwick method (Lambeck & Stanat, 2001a, 2002b), which includes water adjustment skills, longitudinal rotations, sagittal rotations, and swimming skills. Sessions consisted of three parts: (1) The first five minutes of each session were devoted to a structured group activity with six children and their instructors. This part encouraged mental adaptation to the aquatic environment and was accompanied by rhythmic children s songs that were repeated throughout the program. (2) The second part consisted of a 20-minute period during which children practiced individually or in pairs according to treatment goals. (3) The last five minutes of each session were devoted to group activities and children s songs, and were aimed at ending the session and disengaging the children from the aquatic environment. Exercise Intervention Children in the exercise group were placed in a different kindergarten and administered two weekly, individualized, 30-minute land-based activities as part of their educational curriculum. Activities consisted of (1) an additional physiotherapy session once a week, and (2) an adapted activity program once a week. A certified instructor conducted the adapted activity program. Program objectives were to improve fundamental motor skills such as walking, stepping over obstacles, climbing, catching, and throwing objects. 78

11 The Effects of Aquatic Intervention on Energy Expenditure Statistical Analysis Repeated measure analyses of variance were conducted for each dependent variable. Because of the small number of participants in each group, the effect sizes of repeated measures within each group were calculated. T-tests were computed to ensure similarity between groups at the pre-test. Results No significant differences were found between the groups across measures before the intervention period, as measured by T-tests. To examine changes in the measures between the groups before and after the intervention periods, assessment values were compared between the groups (Table 2). Energy Expenditure and Walking Measures Three children in the aquatic intervention group were apprehensive about the mask and therefore did not participate in the metabolic measuring procedures. No significant differences were found between groups for oxygen cost of walking (VO2 m/kg/min). However, in the intervention group there was a trend (p=.076) showing improvement in the oxygen cost of walking, which was not apparent in the control group (Figure 1). Furthermore, based on Cohen s (1988) suggestion, the effect sizes between pre- to post-test results in the aquatic group can be considered to be a moderate main group effect size (.55) compared with the trivial effect size in the exercise group (-.07). The decrease in VO 2 (ml O 2 *kg -1 *m * min -1 ) during walking the distance of 34 meters in the aquatic group was 29%, in contrast to a 4.61% increase in the exercise group. No significant differences were observed between the groups in the energy expenditure index calculated from HR during walking (Table 2). This may be due to the fact that data were collected from a larger number of participants (n=9) in the aquatic intervention group. Group effect sizes in the aquatic intervention can be considered small (.48); by comparison, group effect sizes in the exercise group can be considered trivial (.13). The decrease in energy expenditure index in the aquatic group was 62.95% (Figure 2), compared with a 10.96% decrease in the exercise group. Mean velocity (m * sec -1 ), as measured by the 10-meter walk, increased in the exercise group in both the self-paced and the fast walk compared with the aquatic 79

12 intervention group, but changes were not significant. A stronger trend was present in the self-paced walk (.074). Group effect size (.74) in the exercise group can be considered moderate, compared with a small effect size in the aquatic group (.34). The exercise group showed a 46.78% improvement in walking 10 meters at a self-paced speed, compared with a 15.58% improvement in the aquatic intervention group (Figure 2). The increase in velocity in the fast 10-meter walk was 29.52% in the exercise group (Figure 2) and 20.79% in the aquatic group. 80

13 The Effects of Aquatic Intervention on Energy Expenditure Table 2. Descriptive and Statistical Data Across Energy Expenditure Measures Measure Aquatic intervention Exercise intervention F P Pre-test Post-test ES Pre-test Post-test ES n Mean SD Mean SD Mean SD Mean SD n EEI met EEI Fast SP SP=Self-paced; EE met = Energy Expenditure Metabolic; EEI=Energy Expenditure Index; (p<.05) 81

14 Figure 1. Comparison of groups in pre-test to post-test means of oxygen consumption % Figure 2. Comparison of groups in the change in percentage between pretest and post-test measures 82

15 The Effects of Aquatic Intervention on Energy Expenditure Motor Activity Measures Descriptive and statistical data comparing pre- and post- tests of the groups are presented in Table 3. No significant changes were found between or within groups in the 66-itm GMFM score, nor between groups in GMFM scores on dimensions D and E (.76). No significant differences were found in the GMFM scores on dimension D (.37) or E (.47). However, descriptive evaluation of mean averages between groups showed a 1.29% increase in GMAE scores while the aquatic group showed a 3.52% decrease. Differences in the mobility domain of PEDI were statistically significant in the aquatic intervention group (r=.02, p<.05) but no differences were observed in the exercise group. No significant changes were found between groups in the self-care domain, however mean averages between groups showed a 1.5% decrease in function in the exercise group compared to a 5.66% increase in function in the aquatic group (Figure 3). % Figure 3. Change in percentage between pre-test and post-test motor activity measures between groups 83

16 Table 3. Descriptive and Statistical Data of Group Scores Across Motor Activity Function Measures Measure Aquatic intervention Exercise intervention F P Pre-test Post-test ES Pre-test Post-test ES n Mean SD Mean SD Mean SD Mean SD n GMFM D +E D E Pedi MD * Pedi SC Aim MD = mobility domain; SC=self-care domain. *P<.05 84

17 The Effects of Aquatic Intervention on Energy Expenditure Discussion This study compared the effects of aquatic interventions and land -based interventions on energy expenditure and motor function in children with cerebral palsy (CP). Based on effect sizes, results suggest that aquatic intervention improved energy expenditure during walking as measured by VO2 consumption, and produced a considerably better energy expenditure index than did the exercise intervention. In the metabolic measurement a trend toward a significant group effect was apparent (p=.76). This finding suggests that aquatic intervention affects muscular endurance and aerobic function better than does land-based exercise. The characteristic of buoyancy in the aquatic environment allows children a wide range of movements that are restrained on land because of gravitational constraints. In addition, HR and oxygen uptake during exercise are lower in water than on land (Darby & Yaekle, 2000; Svedenhag & Seger, 1992). This favorable condition apparently increases time on task and intensity of exercise throughout the intervention session. Matsumotot et al. (1999) reported an increase of aerobic capacity in children with bronchial asthma who participated in a swimming training program six times per week for two 15-minute sessions for a six week period. These assumptions are consistent with findings of a recent study showing an increase in treadmill walking duration in five children with CP between the ages of 4-6 who participated in an aquatic intervention program (Getz & Hutzler, submitted for publication). Furthermore, improved equilibrium reactions during forward movement may reduce energy expenditure during walking (Duffy et al., 1996). Hydrostatic pressure supports the body and decreases the number of motor units required to support the upper trunk in maintaining an upright posture. This may allow children to use their upper extremities for equilibrium protective extension reactions rather than using the arms for trunk stabilization, which is the pattern presented on land (Mano, 1994; Woledge & Baum, 1996). In addition, the buoyancy of the water enables initiation of voluntary upper extremity movements that are difficult to initiate on land because of gravitational weight bearing constraints. From a dynamic systems perspective it may be argued that manipulating weight bearing by means of buoyancy may be used as a control parameter triggering pattern generators and shifting toward locomotor activity. The viscosity of the water prolongs the falling time and enables 85

18 children with CP to experience movement patterns that allow the center of gravity to be outside the base of support in all planes. These movement patterns are difficult to explore on land because of the fear of falling. It must be noted that children moved at water depth of chest level, thus bearing 25% of their body mass (Becker & Cole, 2004). In the aquatic environment weight bearing and equilibrium reactions can be controlled by altering the two main forces that affect the posture of the body: buoyancy and viscosity (Becker & Cole, 2003; Lambeck & Stanat, 2001a; 2001b). Children in the exercise group showed greater improvement than the aquatic group in walking the 10-meter distance both at self-paced and fast speeds. The improvement was more noticeable in the self-paced walk, which was expected because the fast walk requires higher degrees of interlimb coordination (Maltais, Bar-Or, & Pierrynowski, 2001). When comparing pre- and post-test means, both groups showed a slight increase in walking velocity. The second aim of the study was to compare the effects of aquatic and land-based exercise intervention on gross motor function. Our primary result was a significant improvement (r=.02, p<.05) in the PEDI mobility domain among the aquatic intervention group in contrast to the exercise group. But these findings were not associated with results obtained in GMFM domains D and E, where no significant pre- to post-test differences were found in either group. When observing the mean average differences between groups, the exercise group showed improvement while the aquatic group did not. These results suggest that GMFM items in dimensions D and E appear require a more precise control and stability of trunk and lower extremities and reflect the ability to complete a specific task. PEDI mobility domain items are scored with respect to the capability of coping with a task in a given environmental context (Ketelaar, 1999). Five out of the 13 sections of the PEDI mobility domain (Haley, et al., 1992) relate to outdoor locomotion, which requires prolonged activity. Damiano, Mark and Abel (1998) reported that strength training in 11 children with CP improved gross motor function and walking velocity but did not affect energy expenditure. Parker and colleagues (1993) studied the relationship of the anaerobic power of legs and arms and of their aerobic power to the 88-item GMFM in 23 children between the ages of 9-13 with spastic CP. They found a good relationship between anaerobic capacity and dimensions D (r=.79, p<.005) and E (r=.83, p<.005) of GMFM. However, they did not find a relationship between aerobic fitness and GMFM scores, and 86

19 The Effects of Aquatic Intervention on Energy Expenditure concluded that GMFM should not be considered a suitable tool for measuring aerobic fitness. In sum, our findings indicate that land-based exercise appears to improve performance in short-term tasks requiring exact coordination with respect to weight bearing activities. Aquatic exercise appears to produce more favorable outcomes in prolonged non-specific weight bearing activities. We recommend both land-based and aquatic interventions to be incorporated together in an intervention program designed to increase function in children with CP. The main limitation of the study was the number of participants in each group, which limited our ability to derive statistical significance. Furthermore, because of ethical limitations we were unable to randomize the placement of children in each intervention group; nevertheless, children in each group were matched as closely as possibly in age and GMFCS levels. 87

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