Cerebral palsy (CP) is the most common cause of movement disorders in children, with a prevalence of 2 to 3 per 1,000 live births1. It is characterized by nonprogressive damage to the immature brain, leading to significant motor impairments, including disturbances in movement and posture2. These deficits often result in restricted daily activities, including gait function3.
Currently, neurodevelopmental and task-oriented approaches and robot-assisted walking therapy, are effectively used to treat the motor development of children with CP4,5. However, it is difficult to effectively engage children’s interests, as they are generally more focused on therapists in the treatment room, and they are also averse to repetitive training, which can lead to poor treatment compliance.
Equine-assisted activities and therapies (EAATs) are broad terms that involve any horse-related activities or therapies. EAATs integrate hippotherapy (an integrated therapeutic program) and therapeutic riding (derived from recreational activities). In the EAAT program, the therapist controls the horse to influence the rider’s posture, balance, coordination, strength, and sensorimotor systems, while the rider interacts with the horse and responds to the movement of the horse. Recently, EAATs have attracted attention as an alternative treatment to improve gross motor function in children with CP who have limited opportunities for leisure activities6. While the horse is walking, the child receives many impulses from the horse’s back; the child responds by trying to maintain their position on the horse to avoid falling7. Improvements in gross motor function, posture, lower limb spasticity, asymmetry, and gait function have been reported after EAAT, as well as an increase in core-muscle strength, limb muscle strength, and sense of balance through this process8,9.
However, although several studies have been conducted on the effects of EAAT on gross motor function, most have explored the immediate effects of EAAT10,11, and only a few have comprehensively reported the results of objective analyses, such as measuring balance ability and analyzing muscle activity using surface electromyography (EMG).
Therefore, this study aimed to investigate the effects of the short-term EAAT program on muscle activity, balance ability, and motor function quantitatively and qualitatively in nine cases of CP in children and to understand if their improvements, if any, persist beyond the treatment period. Our preliminary findings suggest the potential benefits of a short-period EAAT program on gross motor function in children with CP.
This study was approved by the Institutional Review Board and Ethics Committee of the Jeju National University Hospital (No. 2021-05-005-002). Informed consent was obtained from each participant or their guardians.
This study was conducted on nine children with CP who underwent EAAT between July 29, 2021 and August 14, 2021. The inclusion criteria were children aged 5 to 15 years with Gross Motor Function Classification System (GMFCS) stages I to III. The exclusion criteria were chemodenervation, such as Botulinum injection, received within the previous 6 months; selective dorsal rhizotomy performed within the previous 1 year; severe intellectual disability; uncontrolled convulsions; and vision or hearing impairment.
EAATs were performed eight times (thrice a week) between July 29, 2021, and August 14, 2021. Between the first and second sessions, the participants handled the horses, including touching, feeding, grooming, and understanding how to approach the horses. Between the third and eighth sessions, the children rode the horses and learned basic riding postures, including actions such as starting and stopping, changing direction, turning, and navigating obstacles. In the program, the riding time per round was 30 minutes in total, and for the first 5 minutes after riding, a brief warm-up exercise was conducted, and time was allocated to interact with the horse. Five minutes before the end, a simple finishing exercise was performed while riding. Throughout the EAAT program, the guardian closely observed if the program was going well. If participants felt uncomfortable or were reluctant to participate in the EAAT, the program was discontinued with the guardian’s consent. Events such as a fall or unexpected outcomes were immediately reported to the persons in charge of this study.
The Gross Motor Function Measure (GMFM)—which has subsequent GMFM-88 and GMFM-66 versions12—is the most common evaluation tool to measure gross motor function over time for children aged 5 months to 16 years with disabilities. The GMFM-66 is a revised version of the GMFM-88 that uses Rasch analysis; in total, 22 of the original 88 items in the GMFM-88 were deleted to improve reliability and validity13.
The Pediatric Balance Scale (PBS) was used to evaluate balance ability. The PBS is a modified version of the Berg Balance Scale intended for pediatric use and has been proven effective in children with CP. It comprises 14 items, each scored on a scale of 0 to 4, with a maximum score of 5614.
To evaluate balance objectively, we utilized BioRescue static posturography (RM Ingenierie). This method has been used in previous studies on children with CP to measure various parameters of balance15,16. It provides excellent inter-rater and intra-rater reliability, especially in footprint area measurements17. During testing, children stood barefoot on the BioRescue force plate and the vertical pressure fluctuations in the heel and toes of both feet were measured. Balance ability was quantitatively calculated by obtaining weight distribution indices using BioRescue.
The weight distribution index (WDI) was maintained barefoot on the force plate. The pressure and surface area in contact with the foot were obtained from the left and right sides, and the ratio was determined by dividing the smaller value by the larger value. In cases of participants who required assistance while standing, the test was conducted by holding a bar mounted on the BioRescue system. The test was performed for 1 minute with eyes open and subsequently for 1 minute with eyes closed. An ideal state was considered when the child’s weight was evenly distributed on both sides and the WDI value was set to 1.
The limit of stability, which is an index of balance ability, was evaluated thereafter. The body was moved as far as possible in the direction of the arrow shown on a screen without moving the feet. Subsequently, when the arrow disappeared from the monitor, the body was moved back to its original position in preparation for the next balance exercise, also dictated by an arrow’s direction. Because each arrow’s direction was set differently, the area value for each direction was obtained. This enabled the investigation of the sectorization of balance problems regarding the original weight-bearing positions. Using the area values for each direction, the numerical values between each were calculated by dividing the smaller values by the larger values; this was done for the left and right and for the front and rear sides. The values of a limit of stability (left/right and front/back) indicate that the dynamic balance is equal on left/right and front/back when the value is 1. Values close to 1.0 indicate improved dynamic balance.
Lastly, stabilization capacity was evaluated to assess the ability to maintain postural and kinetic aptitude. The participant stood with both feet on the BioRescue force plate for 1 minutes, with eyes opened, to determine how the center of pressure shifted. The exercise was repeated with the participant’s eyes closed to assess how the center of pressure shifted under those conditions. The higher the stabilization capacity index, the more unstable the posture.
Surface EMG was performed to monitor changes in the activity of core muscles during the gait cycle, providing an objective measure of motor function changes in response to the EAAT in children with CP. Surface EMG allows for the most reliable assessment of muscle activation, as the magnitude values obtained from peak root mean square (RMS) are directly related to this factor18. Surface EMG was performed using a portable wireless eight-channel surface electromyograph–FREEEMG (BTS Bioengineering). The peak RMS of the bilateral paraspinal muscles at the L2 level, external oblique anterior, rectus femoris, and semi-tendinosus muscles was obtained through surface EMG during a single gait cycle. The motor points of the muscles were identified for electrode attachment, and the skin was cleaned with 70% alcohol to reduce bioimpedance. Data were analyzed and processed using SMART ANALYZER (BTS Bioengineering) and central core SMART DX (BTS Bioengineering).
Total skeletal muscle mass, trunk skeletal muscle mass, and body fat mass were calculated using a body water meter (BWA 2.0; InBody Co., Ltd.). All evaluations were conducted before and within 1 to 2 months and 12 to 13 weeks after EAAT.
A well-trained physical therapist evaluated GMFM-66 scores, PBS scores, and BioRescue static posturography data, and a clinical technician evaluated surface EMG, muscle mass, and body fat measures. As the evaluator did not have access to the participants’ information, bias that may have occurred during the evaluation was minimized.
The collected data remained secure by allowing access only to the principal researcher. The computer used was password-protected to increase security.
The sample size of nine participants was chosen based on the feasibility and availability of eligible individuals. The intent is to provide a descriptive and exploratory analysis of the intervention’s effects, acknowledging the limitations of generalizing from a small, non-random sample.
The children’s age, sex, height, weight, body mass index (BMI), type of CP, number of paralyzed sides, and GMFCS level were identified. Descriptive statistics were employed to detail individual changes over time. Furthermore, Supplementary Tables 1 and 2 have been included to provide additional detailed analyses, offering a comprehensive view of the data. The Wilcoxon signed-rank test was performed to compare the peak amplitude values of the GMFM-66 and PBS scores, WDI, surface EMG data, skeletal muscle mass, and body fat mass before and at 1–2 and 3 months after the EAAT program. A p-value of <0.05 indicated statistical significance. All statistical analyses were performed using STATA version 14 (Stata Corp.).
Table 1 shows the baseline characteristics of the participants in this study, including six boys and three girls with ages ranging from 6 to 14 years. All nine participants had spastic CP; the three participants had unilateral paralysis, while six had bilateral paralysis. Four, three, and two participants had I, II, and III GMFCS stages, respectively.
Table 1 . Baseline characteristics of study participants
| Case No. | Age (yr) | Sex | Height (cm) | Weight (kg) | BMI (kg/m2) | Type of CP | Paralyzed side | GMFCS |
|---|---|---|---|---|---|---|---|---|
| 1 | 11 | Male | 142 | 53 | 26.28 | Spastic | Bilateral | 2 |
| 2 | 9 | Female | 132 | 37 | 21.24 | Spastic | Unilateral | 1 |
| 3 | 14 | Male | 170 | 56 | 19.38 | Spastic | Unilateral | 2 |
| 4 | 14 | Male | 151 | 61 | 26.75 | Spastic | Bilateral | 1 |
| 5 | 9 | Male | 138 | 46 | 24.15 | Spastic | Unilateral | 1 |
| 6 | 8 | Female | 114 | 23 | 17.70 | Spastic | Bilateral | 3 |
| 7 | 6 | Male | 111 | 23 | 18.67 | Spastic | Bilateral | 2 |
| 8 | 11 | Male | 130 | 35 | 20.71 | Spastic | Bilateral | 3 |
| 9 | 8 | Female | 126 | 27 | 17.01 | Spastic | Bilateral | 1 |
BMI: body mass index, CP: cerebral palsy, GMFCS: Gross Motor Function Classification System.
Table 2 shows the GMFM-66 and PBS scores at baseline, immediately after the EAAT, and 3 months after the EAAT. The mean (standard deviation) GMFM-66 score was 70.556 (13.693), and the mean PBS score was 41.667 (16.454) at baseline. Case 9 was the only child whose GMFM-66 score decreased 3 months after EAAT compared to baseline. The rest of the children showed improvement in their scores in the 3 months after EAAT compared to baseline. In Case 3, there was no change in PBS scores at baseline, after EAAT, and 3 months after EAAT. In Cases 5 and 9, the PBS score was confirmed to decrease 3 months after EAAT compared to baseline. In Case 9, both GMFM-66 and PBS scores were observed to decrease. Case 5 showed the most improvement in the GMFM-66 score, and Case 1 showed the most improvement in the PBS score.
Table 2 . Motor function and balance ability measures at baseline, after EAAT, and 3 months after EAAT
| Case No. | GMFM-66 | PBS | |||||
|---|---|---|---|---|---|---|---|
| Baseline | After EAAT | 3 mo after EAAT | Baseline | After EAAT | 3 mo after EAAT | ||
| 1 | 59.6 | 59.1 | 60.9 | 33 | 37 | 38 | |
| 2 | 88.0 | 89.7 | 92.1 | 55 | 55 | 56 | |
| 3 | 89.7 | 81.9 | 92.1 | 56 | 56 | 56 | |
| 4 | 77.5 | 80.0 | 80.9 | 53 | 54 | 55 | |
| 5 | 76.0 | 80.0 | 84.0 | 53 | 52 | 52 | |
| 6 | 54.1 | 55.9 | 56.9 | 19 | 20 | 23 | |
| 7 | 65.6 | 66.0 | 67.4 | 42 | 45 | 45 | |
| 8 | 52.3 | 53.6 | 53.6 | 7 | 10 | 11 | |
| 9 | 72.2 | 71.2 | 70.4 | 50 | 46 | 49 | |
EAAT: equine-assisted activities and therapies, GMFM-66: Gross Motor Function Measure 66, PBS: Pediatric Balance Scale.
Table 3 summarizes the balance and stability values measured using the BioRescue system at baseline, immediately after the EAAT, and 3 months after the EAAT. Cases 1 and 6 showed signs of anxiety about using the BioRescue system; hence, they held the bar attached to the BioRescue system and performed the examination. Case 4 felt anxious only in the test that required their eyes to be closed; hence, they performed the examination while holding a bar and with their eyes closed. Cases 7 and 8 showed poor cooperation and anxiety; hence, the entire BioRescue examination was conducted with the examiner’s assistance, and the limit of stability test could not be performed. No statistically significant changes were observed in the balance and stability values in the Wilcoxon signed-rank test analysis (Supplementary Table 1).
Table 3 . Comparison of quantitative balance and stability function measures at baseline, after EAAT, and 3 months after EAAT
| Case No. | Measurement | WDI-area, eye opened | WDI-area, eye closed | Limit of stability, total surface area | Stabilization capacity | |||
|---|---|---|---|---|---|---|---|---|
| Surface area with eye open | Surface area with eye closed | Length with eye open | Length with eye closed | |||||
| 1 | Baseline | 0.991 | 0.912 | 3,330 | 4,192 | 7,022 | 207.0 | 178.2 |
| After EAAT | 0.976 | 1.000 | NT | 2,833 | 388 | 144.6 | 45.8 | |
| 3 mo after | 0.932 | 0.953 | NT | 6,157 | 6,387 | 171.6 | 182.1 | |
| 2 | Baseline | 0.804 | 0.917 | 2,246 | 41 | 254 | 40.9 | 57.7 |
| After EAAT | 0.800 | 0.917 | 1,623 | 218 | 311 | 52.2 | 70.0 | |
| 3 mo after | 0.934 | 0.925 | 7,504 | 97 | 67 | 38.0 | 41.4 | |
| 3 | Baseline | 0.835 | 0.793 | 19,451 | 77 | 190 | 36.3 | 38.0 |
| After EAAT | 0.974 | 0.872 | 14,314 | 114 | 195 | 35.8 | 41.5 | |
| 3 mo after | 0.968 | 0.929 | 19,070 | 90 | 116 | 36.4 | 29.2 | |
| 4 | Baseline | 0.685 | 0.685 | 3,601 | 202 | 156 | 28.4 | 23.6 |
| After EAAT | 0.796 | 0.766 | 4,417 | 179 | 149 | 34.4 | 22.4 | |
| 3 mo after | 0.821 | 0.772 | 8,426 | 2,928 | 273 | 201.9 | 43.8 | |
| 5 | Baseline | 0.821 | 0.689 | 4,146 | 496 | 151 | 58.1 | 55.2 |
| After EAAT | 0.933 | 0.909 | 2,532 | 246 | 672 | 53.6 | 109.9 | |
| 3 mo after | 0.867 | 0.824 | 3,294 | 423 | 2,162 | 56.0 | 90.1 | |
| 6 | Baseline | 0.850 | 0.876 | 6,306 | 1,369 | 361 | 83.8 | 41.2 |
| After EAAT | 0.710 | 0.642 | 3,077 | 360 | 236 | 48.3 | 50.9 | |
| 3 mo after | 0.815 | 0.795 | 1,782 | 80 | 106 | 34.8 | 38.0 | |
| 7 | Baseline | 1.059 | 0.960 | NT | 6,347 | 4,022 | 245.2 | 242.9 |
| After EAAT | 0.944 | 0.942 | NT | 2,478 | 2,315 | 179.9 | 227.8 | |
| 3 mo after | 0.974 | 0.949 | NT | 5,914 | 13,367 | 320.4 | 497.4 | |
| 8 | Baseline | 1.000 | 0.955 | 1,121 | 63 | 82 | 30.7 | 29.5 |
| After EAAT | 0.955 | 0.976 | 2,650 | 68 | 37 | 26.6 | 27.6 | |
| 3 mo after | 0.953 | 0.924 | 1,106 | 103 | 170 | 34.0 | 44.3 | |
| 9 | Baseline | 0.893 | 0.957 | 8,981 | 1,003 | 1,154 | 105.6 | 135.9 |
| After EAAT | 0.930 | 0.964 | 6,545 | 1,732 | 2,110 | 142.5 | 171.3 | |
| 3 mo after | 0.905 | 0.979 | 5,721 | 3,392 | 2,216 | 168.5 | 185.8 | |
EAAT: equine-assisted activities and therapies, WDI: weight distribution index, NT: not tested.
Table 4 summarizes the values of peak RMS applied to the bilateral paraspinal muscle, external oblique anterior muscle, rectus femoris, and semitendinosus during the gait cycle at baseline, immediately after the EAAT, and 3 months after the EAAT. Case 1 could not undergo surface EMG because of poor cooperation; thus, the results were analyzed using data of eight participants. No statistically significant changes were observed in the Wilcoxon signed-rank test analysis (Supplementary Table 2).
Table 4 . Comparison of peak RMS of core muscles during the gait cycle at baseline, after EAAT, and 3 months after EAAT
| Case No. | Measurement | PRMF-Lst | PRMF-Lsw | PLMF-Rst | PLMF-Rsw | PREOA-Lst | PREOA-Lsw | PLEOA-Rst | PLEOA-Rsw | PRRF-Lst | PRRF-Lsw | PLRF-Rst | PLRF-Rsw | PRST-Lst | PRST-Lsw | PLST-Rst | PLST-Rsw |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Baseline | NT | NT | NT | NT | NT | NT | NT | NT | NT | NT | NT | NT | NT | NT | NT | NT |
| After EAAT | 36.986 | 11.357 | 38.943 | 24.315 | 43.768 | 10.926 | 28.222 | 26.023 | 37.875 | 21.324 | 37.589 | 28.230 | 25.233 | 21.550 | 15.201 | 0.101 | |
| 3 mo after | 35.171 | 14.239 | 28.689 | 14.627 | 12.334 | 13.841 | 21.969 | 19.717 | 47.460 | 20.219 | 27.990 | 26.466 | 68.88 | 23.580 | 42.003 | 34.482 | |
| 2 | Baseline | 45.500 | 25.980 | 45.785 | 17.959 | 34.338 | 18.839 | 96.113 | 34.302 | 55.518 | 40.203 | 73.348 | 58.157 | 63.424 | 38.813 | 0.004 | 0.002 |
| After EAAT | 27.526 | 13.522 | 55.633 | 56.845 | 33.515 | 30.850 | 62.779 | 21.057 | 54.437 | 24.173 | 44.226 | 25.932 | 118.985 | 69.293 | 294.341 | 85.750 | |
| 3 mo after | 51.858 | 40.223 | 51.518 | 78.165 | 76.546 | 71.168 | 64.397 | 64.397 | 62.894 | 53.201 | 95.193 | 155.336 | 159.78 | 104.603 | 153.839 | 80.275 | |
| 3 | Baseline | 39.229 | 16.645 | 49.100 | 35.267 | 91.507 | 66.449 | 72.146 | 100.300 | 172.646 | 25.023 | 28.889 | 10.909 | 51.928 | 46.320 | 69.144 | 61.973 |
| After EAAT | 37.645 | 12.021 | 28.921 | 13.014 | 49.882 | 40.764 | 40.917 | 56.379 | 41.446 | 17.359 | 35.036 | 11.202 | 54.675 | 35.148 | 123.144 | 56.203 | |
| 3 mo after | 44.886 | 12.233 | 35.901 | 13.188 | 39.926 | 34.117 | 68.351 | 68.898 | 79.535 | 26.260 | 37.249 | 21.945 | 28.094 | 21.477 | 55.308 | 25.714 | |
| 4 | Baseline | 34.489 | 19.147 | 23.739 | 19.393 | 16.564 | 9.970 | 25.260 | 20.166 | 76.471 | 84.472 | 32.157 | 29.225 | 26.453 | 0.232 | 0.003 | 0.002 |
| After EAAT | 24.790 | 20.585 | 22.042 | 15.072 | 12.153 | 13.703 | 15.389 | 14.057 | 21.583 | 22.538 | 29.942 | 15.822 | 51.603 | 29.272 | 71.680 | 31.701 | |
| 3 mo after | 22.984 | 18.007 | 30.476 | 20.832 | 9.849 | 9.975 | 23.843 | 19.343 | 30.719 | 15.719 | 19.938 | 12.438 | 51.873 | 33.631 | 38.781 | 22.443 | |
| 5 | Baseline | 28.696 | 34.125 | 53.671 | 16.477 | 61.565 | 20.339 | 35.314 | 14.426 | 34.802 | 13.567 | 54.669 | 19.538 | 95.732 | 151.013 | 153.726 | 135.342 |
| After EAAT | 33.814 | 16.641 | 43.998 | 19.450 | 63.388 | 32.939 | 113.503 | 117.784 | 37.388 | 18.958 | 37.614 | 12.652 | 76.607 | 57.744 | 85.538 | 63.107 | |
| 3 mo after | 58.167 | 39.135 | 45.387 | 38.012 | 42.255 | 21.908 | 18.657 | 21.905 | 73.122 | 42.069 | 58.564 | 27.862 | 147.093 | 52.108 | 181.879 | 91.342 | |
| 6 | Baseline | 72.328 | 25.024 | 59.757 | 27.222 | 28.364 | 22.901 | 48.272 | 17.461 | 20.466 | 21.004 | 26.734 | 13.658 | 184.642 | 158.509 | 161.530 | 167.254 |
| After EAAT | 84.135 | 34.767 | 83.460 | 31.933 | 32.854 | 18.076 | 54.142 | 27.117 | 255.739 | 67.896 | 30.655 | 34.247 | 211.988 | 150.802 | 176.339 | 159.037 | |
| 3 mo after | 78.431 | 22.521 | 73.180 | 34.038 | 33.595 | 15.831 | 61.563 | 24.241 | 18.613 | 17.955 | 44.893 | 15.034 | 139.57 | 183.392 | 125.644 | 97.542 | |
| 7 | Baseline | 67.329 | 98.415 | 106.293 | 99.599 | 48.509 | 34.201 | 38.931 | 39.955 | 36.569 | 29.657 | 17.055 | 13.363 | 107.823 | 40.984 | 170.285 | 108.713 |
| After EAAT | 147.550 | 65.796 | 98.295 | 83.042 | 104.123 | 111.772 | 68.194 | 56.203 | 149.848 | 46.486 | 59.793 | 50.079 | 172.339 | 143.499 | 151.014 | 153.960 | |
| 3 mo after | 118.014 | 88.878 | 120.307 | 120.307 | 48.137 | 34.893 | 135.305 | 87.762 | 67.928 | 14.687 | 33.936 | 22.703 | 128.18 | 107.433 | 70.013 | 79.416 | |
| 8 | Baseline | 63.180 | 16.822 | 59.675 | 40.952 | 27.223 | 18.270 | 36.658 | 35.031 | 90.445 | 97.060 | 97.981 | 98.347 | 48.546 | 27.839 | 27.201 | 30.520 |
| After EAAT | 50.055 | 28.206 | 86.026 | 108.031 | 46.695 | 22.636 | 93.536 | 128.906 | 84.444 | 89.360 | 134.452 | 161.288 | 100.877 | 59.919 | 108.163 | 119.059 | |
| 3 mo after | 47.817 | 22.489 | 67.874 | 66.609 | 66.843 | 36.159 | 290.349 | 28.406 | 170.336 | 55.790 | 137.241 | 96.534 | 60.528 | 47.662 | 90.392 | 98.143 | |
| 9 | Baseline | 98.566 | 29.949 | 108.098 | 140.490 | 108.003 | 45.473 | 42.347 | 52.516 | 221.075 | 45.807 | 115.938 | 49.525 | 212.644 | 90.781 | 397.178 | 233.190 |
| After EAAT | 110.374 | 42.979 | 92.705 | 75.809 | 71.229 | 31.945 | 37.834 | 48.082 | 125.413 | 40.282 | 196.273 | 44.259 | 148.574 | 120.620 | 269.434 | 230.691 | |
| 3 mo after | 46.503 | 5.744 | 0.009 | 0.003 | 34.477 | 19.102 | 77.538 | 47.706 | 78.735 | 13.429 | 72.370 | 25.049 | 306.242 | 147.982 | 393.286 | 234.244 |
RMS: root mean square, EAAT: equine-assisted activities and therapies, PRMF: peak RMS right multifidus, Lst: left stance, Lsw: left swing, PLMF: peak RMS left multifidus, Rst: right stance, Rsw: right swing, PREOA: peak RMS right external oblique anterior, PLEOA: peak RMS left external oblique anterior, PRRF: peak RMS right rectus femoris, PLRF: peak RMS left rectus femoris, PRST: peak RMS right semitendinosus, PLST: peak RMS left semitendinosus, NT: not tested.
Table 5 shows the skeletal muscle, trunk skeletal muscle, and body fat values at baseline, immediately after the EAAT, and 3 months after the EAAT. Case 3 had the highest skeletal muscle and trunk skeletal muscle values in the entire period. Case 4 had the highest body fat value in the entire period. Cases 5 and 8 showed increased trunk skeletal muscle values immediately after the EAAT.
Table 5 . Comparison of skeletal muscle and body fat values at baseline, after EAAT, and 3 months after EAAT
| Case No. | Measurement | Skeletal muscle (kg) | Trunk skeletal muscle (kg) | Body fat (%) |
|---|---|---|---|---|
| 1 | Baseline | 17.2 | 16.1 | 20.4 |
| After EAAT | 16.6 | 15.6 | 21.4 | |
| 3 mo after | 17.0 | 16.0 | 20.9 | |
| 2 | Baseline | 11.8 | 11.1 | 13.6 |
| After EAAT | 11.7 | 10.4 | 13.5 | |
| 3 mo after | 12.7 | 10.9 | 13.7 | |
| 3 | Baseline | 28.2 | 22.4 | 6.5 |
| After EAAT | 27.9 | 21.9 | 5.9 | |
| 3 mo after | 28.5 | 21.4 | 9.5 | |
| 4 | Baseline | 20.1 | 17.0 | 23.5 |
| After EAAT | 20.3 | 16.6 | 23.1 | |
| 3 mo after | 21.2 | 17.7 | 22.6 | |
| 5 | Baseline | 14.8 | 12.4 | 17.5 |
| After EAAT | 13.8 | 12.7 | 19.5 | |
| 3 mo after | 13.9 | 12.6 | 20.1 | |
| 6 | Baseline | 8.1 | 7.6 | 6.4 |
| After EAAT | 8.1 | 7.6 | 6.0 | |
| 3 mo after | 8.7 | 8.2 | 6.1 | |
| 7 | Baseline | 6.3 | 8.1 | 9.2 |
| After EAAT | 8.8 | 7.5 | 4.7 | |
| 3 mo after | 7.2 | 7.0 | 9.2 | |
| 8 | Baseline | 11.1 | 10.8 | 12.6 |
| After EAAT | 11.0 | 10.9 | 12.8 | |
| 3 mo after | 10.8 | 10.8 | 15.0 | |
| 9 | Baseline | 9.8 | 9.1 | 6.8 |
| After EAAT | 9.6 | 8.8 | 7.3 | |
| 3 mo after | 9.8 | 9.0 | 8.9 |
EAAT: equine-assisted activities and therapies.
This study investigated whether short-term EAAT had immediate effects as well as lasting effects on motor function in nine children with CP. After 3 months of EAAT, an increase in GMFM-66 scores was observed in eight cases, and an increase in PBS scores was seen in six cases, suggesting potential long-term improvements in gross motor and balance functions due to intensive, short-term EAAT.
While most participants showed improvement, Case 9 showed a decline in scores on GMFM, and Cases 4 and 9 showed a decline in scores on PBS at 3 months after EAAT; these score reductions were not large in magnitude. The children who showed a decrease in their scores had relatively good function with GMFCS 1 to 2 at baseline. Feelings of irritation and the lack of motivation during evaluation can greatly affect the results in children; in some children, evaluation was performed after other physical therapy, which may have affected the results.
Previous research has also reported improvements in gross motor function after EAAT. For instance, studies have found increased GMFM-66 scores after 16 EAAT sessions spread over 8 weeks. These studies had the advantage of consistent treatment schedules and control group comparisons10,11. The expected physical effects of the EAAT that would have led to improvement in gross motor function are as follows: rhythmic body movement through horseback riding, torso coordination in response to the movement of the horse that encourages appropriate participant balance and posture, and a wide spectrum of sensory and motor stimuli provided by the horses19,20. The slow, rhythmic movement of the horse promotes the development of the child’s paraspinal muscles, and the multifaceted swinging rhythm of the horse improves the child’s pelvic girdle. These promote the typical pelvis movements that occur during normal walking. Moreover, the EAATs have an entertaining effect and promote treatment compliance, resulting in improved participant balance, mobility, and posture21-24.
Conversely, studies by Žalienė et al.23 and Davis et al.24 did not report consistent improvements in motor function after EAAT, possibly owing to inconsistent treatment durations among participants and the absence of a control group. Additionally, the 1-week gap between EAAT sessions in these studies may have been too long to provide improvements in muscle strength or balance23,24. In particular, the study of Žalienė et al.23, similar to ours, involved an intensive EAAT program over a short-term period (10 sessions in 2 weeks) for the beginner group. Similar to our study, their study did not show immediate improvement in gross motor function.
Most previous studies have compared the effects before and immediately after the EAAT10,11,23-25. Unlike previous studies focusing on immediate posttreatment effects, our study contributes new insights into the long-term impacts of EAAT, an aspect not extensively explored before.
Although caution is needed in interpreting the results owing to the small sample size inherent to a case series, this study demonstrated improvements in gross motor function in more than half of the cases, allowing for the consideration of several reasons underlying the long-term effects of such short-term, intensive EAAT. Through the EAAT, core-muscle engagement gradually increased in participants, and the amount of movement in daily life increased; this appears to be a long-term effect, as it was observed 3 months after the EAAT. Improved self-confidence is also thought to be a long-term effect of the EAAT. This increase in self-confidence triggers a child’s willingness to explore and learn new motor activities. To confirm these suppositions, it is important to develop a method to quantitatively assess the physical activity of participants with CP both during and after the EAAT using a wearable device such as a smartwatch.
During the riding time, lateral flexion, extension, and rotation occur in the participants’ back, which reduce the spasticity of the back, pelvis, and lower limbs8,23,25 and can also improve energy expenditure26 and muscle symmetry8. Lower limb spasticity and thigh adductors’ asymmetry cause a lack of pelvic and trunk dissociation. Therefore, this improvement is meaningful, as it reduces the strength imbalance and disturbance of the torso muscles23. Accordingly, gross motor function is expected to improve even after 3 months of the EAAT in children with CP.
When performing the BioRescue examination, some participants required assistance, such as holding the examiner’s hands or a bar attached to the BioRescue equipment, owing to feelings of anxiety and fear of falling. This inconsistency in providing assistance was considered a limitation, as it was not uniformly applied to all patients, and might have led to a lack of consistency in the BioRescue test results, warranting greater caution in their interpretation. However, the observed increase in PBS scores in many children suggests that more substantial and significant results could be achieved in more quantitative tests like the BioRescue, particularly in future studies with a larger sample size. In addition, as reported in a previous study27, the number and duration of EAAT sessions in this study might not have been sufficient to achieve statistical significance. This highlights the importance of considering session frequency and duration in future EAAT research to fully assess its effectiveness.
Muscle activity, as measured through surface EMG, did not demonstrate a consistent increasing or decreasing trend. Notably, one child was unable to undergo the test, and even when the Wilcoxon analysis was conducted on data from the remaining eight participants, no significant results were obtained (Supplementary Table 2). Previous studies23,28,29 have reported inconsistent results regarding whether the EAAT improves muscle strength and gait parameters. This inconsistency may partly stem from the inherent limitations of using surface EMG for measuring balance and stability. The variability in attachment sites and the method’s poor repeatability can lead to challenges in drawing precise comparisons and firm conclusions about real improvements in balance, particularly in a longitudinal study design. These factors underline the complexity of assessing the true impact of EAAT on muscle activity and balance over time.
The observed changes in skeletal muscle and body fat following EAAT, as shown in Table 5, provide interesting insights, albeit without statistical significance. As with previous research on the neuromuscular effects of EAAT30, we observed a tendency for both skeletal muscle and body fat levels to increase after EAAT. However, these changes did not reach statistical significance across all cases (Supplementary Table 3). This absence of significant findings may be due to the small sample size, underscoring the necessity for larger-scale studies.
This study has some limitations. First, the sample size was small. Although the GMFM-66 score was set as the primary outcome at the research planning stage, and the sample size was calculated to recruit an adequate number of participants, this seemed insufficient to obtain significant results for the secondary outcomes, including the balance index, stability index, muscle activities, and muscle amount. Second, the inclusion of participants receiving other treatments introduces potential confounding factors that may impact the interpretation of the effectiveness of the EAAT. Third, owing to the small sample size, it was impossible to analyze subgroups according to the GMFCS stage and age. Children with originally good GMFCS stages may benefit more from the EAAT, even if they are of the same spastic type9,14, and younger children have a higher potential for improvement than older children14. There was no control group to compare the effectiveness of the EAAT with conventional treatment. Future studies might benefit from the inclusion of larger and more diverse cohorts to validate these preliminary findings and explore subgroup responses more thoroughly. Fourth, in the EAAT, each horse’s movement, communication between children and horses, children’s adaptability, and horses’ adaptability are different, affecting the treatment effect on children. However, these traits are difficult to control, as they are distinct to each individual and horse. To address this limitation, comparing EAAT, horse-simulator exercise, and general treatment control groups may determine which treatment is more effective for gross motor function. Lastly, the technical challenges with surface EMG, such as variable electrode placement, highlight the need for more standardized methods to ensure the reliability of muscle-activity measurements.
Nevertheless, the strength of this study is that objective results were obtained by quantitatively analyzing surface muscle activity, balance, and muscle mass and evaluating the GMFM-66 and PBS scores in children with CP. Moreover, as the function and objective indicators 3 months after the end of treatment were presented, it demonstrated that the effect of the EAAT could be helpful in the long term. While a case series provides preliminary insights rather than conclusive evidence, this case series serves as a valuable starting point for exploring the effects of EAAT. To build on these findings, future studies should consider larger and more diverse cohorts and should incorporate randomized control groups.
In conclusion, our preliminary findings suggest that short-term EAAT might have potential as an intervention for long-term motor improvement in children with CP. Further researches with larger sample sizes and more diverse cohorts are needed to validate these results.
Supplementary Materials can be found at https://doi.org/10.5763/kjsm.2024.42.1.12.
kjsm-42-1-12-supple.pdfThis work was supported by a research grant from Jeju National University Hospital (Jeju, Korea) in 2021. The funding body had no involvement in the study design; collection, management, analysis, and interpretation of data; or the decision to submit for publication.
No potential conflict of interest relevant to this article was reported.
Conceptualization, Funding acquisition: HJL. Methodology: HJL, SWS. Formal analysis: SJL, SWS, HJL. Project administration: all authors. Visualization: SWS, MSS. Writing–original draft: SJL HJL. Writing–review & editing: all authors.
