Research Design

This study is an experimental study with pre- and post-test control group design.

Participants and Sampling

The study recruited 105 women aged 65 and older from a project at Alanya Alaaddin Keykubat University. All potential participants received detailed information about the study. Initial comprehensive medical evaluations, including history, physical assessment, and specialist consultations, determined eligibility for aquatic or land-based exercise programs. Additional tests (radiological, biochemical, hematological, ECG) and cardiology consultations were conducted as needed.

Using convenience sampling, 45 eligible participants were randomly allocated into three groups (n = 15 each): Aquatic Exercise Group (AEG), Land-based Exercise Group (LEG), and Control Group (CG). Participants who were non-compliant or did not complete post-tests were excluded, resulting in a final sample of 33 women (AEG = 9, LEG = 14, CG = 10) (Figure 1).

Figura 1 Diagrama de flujo del reclutamiento de participantes y la asignación a los grupos.  

Figura 1. Flow chart of participant recruitment and groups allocation. 

As presented in Table 1, the mean body mass index (BMI) of participants was 30.82 ± 3.3 kg/m² in the Aquatic Exercise Group (AEG), 29.63 ± 6.4 kg/m² in the Land-based Exercise Group (LEG), and 29.14 ± 3.7 kg/m² in the Control Group (CG). Baseline comparisons among the AEG, LEG, and CG groups demonstrated no statistically significant differences in weight (p = 0.701), height (p = 0.656), or BMI (p = 0.758). These results confirm the homogeneity of the groups with respect to key anthropometric characteristics prior to the intervention.

To ensure study safety and internal validity, strict inclusion and exclusion criteria were applied. Inclusion criteria required participants to have no severe cardiovascular, neurological, or musculoskeletal conditions; be independently ambulatory; have no falls in the past six months; obtain medical clearance for exercise; and provide informed consent. Exclusion criteria encompassed advanced osteoporosis, epilepsy, significant sensory impairments, medications affecting balance or mobility, and irregular attendance. Additionally, participants were screened using the Physical Activity Readiness Questionnaire (PAR-Q), with only those deemed low-risk included in the exercise programs.

Intervention and Implementation Process

Based on evidence supporting multicomponent exercise for older adults, this study’s intervention adhered to established protocols proven to enhance functional capacity (^{Aquatic Exercise Association, 2017}; ^{Martínez-Rodríguez et al., 2022}). Both the Aquatic Exercise Group (AEG) and Land-based Exercise Group (LEG) engaged in 60-minute sessions, thrice weekly for eight weeks, each comprising a 10-minute warm-up, 40-minute main exercise, and 10-minute cool-down (see Table 2).

Aquatic Exercise Program (AE). Conducted in a temperature-controlled indoor Olympic pool (water: 28.5 - 30°C; air: 26 - 29°C; depth: 1.1 m), participants unfamiliar with aquatic exercise received two orientation sessions to ensure safety and proper technique. Exercises paralleled the land-based regimen, utilizing progressive resistance bands (yellow to black). Adherence was reinforced via reminder calls and make-up sessions, supported by motivational strategies.

Land-Based Exercise Program (LE). Held in a dry area adjacent to the pool, sessions targeted muscle strength, flexibility, balance, agility, and cardiovascular endurance. Resistance bands progressed systematically from yellow to black to match participants’ improving capacity.

Table 2 below presents the session plan and content applied in the warm-up, main exercise and cool-down phases of the AEG and LEG programs.

The structure and progression of resistance intensity, volume, and rest intervals across the 8-week intervention are summarized in Table 2, providing a detailed framework for replication and clarity regarding training load management.

Outcomes Measures

Data collection comprised three phases: pre-test, intervention, and post-test. At pre-test, participants’ height, weight, and BMI were recorded, followed by a 20-30 min battery of functional fitness tests.

The AEG completed a water-based resistance training program in an Olympic-sized pool, 60 minutes per session, three times weekly for eight weeks. LEG followed an identical protocol on land. The CG maintained usual activities without intervention but were offered the exercise program post-study if significant benefits were observed.

The overall study design is detailed in Table 3. The general structure of the experimental plan applied in the study is summarized in Table 3 below.

The independent variable of the study was the type of exercise administered (aquatic or land-based). The dependent variables were defined as participants’ body composition (weight, Body Mass Index) and functional fitness levels, including muscular strength, flexibility, balance, agility, and endurance.

Data Collection Tools

Physical function was assessed using the Senior Fitness Test (SFT) (^{Rikli and Jones, 2013}), which includes seven standardized tests:

Back Scratch Test (BST): Assesses upper body flexibility via the distance between overlapping or non-overlapping middle fingers when reaching behind the back.

Chair Sit-and-Reach Test (CSRT): Measures lower extremity flexibility by assessing reach distance while seated.

Biceps Curl Test (BCT): Evaluates upper limb strength through the number of biceps curls performed in 30 seconds using a 2.27 kg (female) or 3.63 kg (male) dumbbell.

Chair Stand Test (CST): Measures lower limb strength by counting full stands from a seated position within 30 seconds.

6-Minute Walk Test (6MWT): Assesses aerobic endurance based on the total distance walked in six minutes on a 10-meter track.

Hand Grip Strength Test (HGST): Determines grip strength using a dynamometer; the best of two attempts was recorded in kilograms.

8-Foot Up-and-Go Test (8FUG): Assesses agility and dynamic balance through timed completion of standing, walking around a cone 2.44 m away, and sitting back down.

Body composition was evaluated via Body Mass Index (BMI), calculated using the standard formula: BMI = weight (kg) / height² (m²). To complement these, two validated balance assessments were administered:

Berg Balance Scale (BBS): Comprising 14 tasks (e.g., standing, reaching, turning), scored 0 - 4 per item (max 56), this test evaluates functional balance capacity (^{Berg et al., 1989}).

Tinetti Balance and Gait Assessment (TBT): Includes 9 balance and 7 gait items, scored 0-2 each (max 28), providing a combined balance and gait profile (^{Tinetti et al., 1990}).

Statistical Analysis

Data were analyzed using SPSS software version 25.0. Given the sample size was less than 50, normality of the data distribution was assessed using the Shapiro-Wilk test. Homogeneity of variances was evaluated with Levene’s test, while homogeneity of mean differences was examined through either ANOVA or Kruskal-Wallis tests, as appropriate. For within-group comparisons of pre- and post-test scores, paired samples t-tests were employed for normally distributed data, whereas the Wilcoxon signed-rank test was applied for data that did not meet normality assumptions. A significance level of p < 0.05 was adopted for all statistical analyses.

Ethical Considerations

The research protocol was reviewed and approved by the Clinical Research Ethics Committee of Selçuk University (Approval Number: 40, Date: 04,04,2024). All participants were informed in detail about the purpose, procedures, and potential risks of the study. Written informed consent, approved by the ethics committee, was obtained from each.

Body Composition

Our findings revealed a significant improvement in body composition exclusively within the land exercise group (p < 0.05), indicating the potential of land-based interventions for weight management in older adults. However, the lack of significant change in BMI suggests that the program’s duration and intensity may have been insufficient to affect this metric.

In contrast, the aquatic exercise group showed no significant changes in body composition. This may be due to the buoyancy effect of water, which reduces gravitational load and mechanical stress on muscles and bones, potentially limiting metabolic stimuli required for fat loss and muscle hypertrophy. Additionally, the relatively short duration (8 weeks) and moderate intensity of the aquatic program might have constrained observable changes.

Previous studies have reported mixed results regarding the effects of aquatic exercise on body composition. ^{Irandoust and Taheri (2015)} observed significant improvements in BMI, waist-to-hip ratio, body fat percentage, and muscle mass following a 12-week aquatic exercise program. Similarly, ^{Bergamin et al. (2013)} reported positive outcomes in body composition after 24 weeks of water-based training. ^{Buitrago-Restrepo et al. (2024)} also concluded in their systematic review and meta-analysis that aquatic exercise contributes to improvements in lower limb muscle power and overall physical performance in older adults. These studies highlight that the effectiveness of aquatic exercise is influenced by factors such as program duration, intensity, and structure.

The discrepancy between the lack of significant change in our aquatic exercise group and the positive outcomes reported in previous literature, may be attributed not only to program parameters but also to the baseline functional levels and characteristics of the participants. Therefore, to enhance the effects of aquatic exercise on body composition, longer and more intensive interventions may be recommended.

Importantly, aquatic exercise offers a low-impact, supportive, and safe environment, facilitating participation among older adults with balance impairments or joint issues. This supports its use for populations at high risk of falls or musculoskeletal limitations, despite limited impact on body composition. In summary, while land-based exercise appears more effective for improving body composition, aquatic exercise’s safety and functional benefits make it a valuable option for certain high-risk groups.

Functional Fitness

Significant functional fitness improvements were noted in the aquatic exercise group, including enhanced aerobic endurance, upper and lower extremity strength, flexibility, agility, and balance (p < 0.05). Handgrip strength did not improve significantly (p > 0.05), suggesting the need for targeted resistance training to address this parameter.

These results align with ^{Kieffer et al. (2012)} who reported positive effects of short-term aquatic exercise on functional strength and agility. ^{Oh and Lee (2021)} similarly found greater improvements in hip strength, balance, and quality of life with aquatic versus land exercise. ^{Suomi and Collier (2003)} also demonstrated that aquatic exercise benefits older adults with arthritis, particularly in balance, supporting our findings. In the assessment of aerobic endurance, while the aquatic exercise group showed significant improvements in the six-minute walk test results (p < 0.05), no similar enhancement was observed in the land-based exercise group (p > 0.05). This suggests that the intensity and content of the land-based program were insufficient to elicit improvements in aerobic capacity, highlighting the need for future interventions to more directly target this parameter. Similar findings reported by ^{Oh and Lee (2021)} further support this interpretation.

The study conducted by Takeshima et al. (2022) reported that water-based exercises promoted multidimensional physical development in elderly women. This finding is consistent with the significant improvements observed in flexibility, agility, and muscular strength in our study (p < 0.05). However, the absence of significant improvement in handgrip strength in both studies suggests that exercises specifically targeting grip strength may not have been adequately implemented.

A thesis by ^{Yüzlü (2014)} comparing aquatic and land exercise effects on older adults reported no significant differences between groups but noted overall functional improvements, similar to our findings. Our data, however, suggest that aquatic exercise may confer superior benefits in balance, agility, and aerobic endurance, likely due to enhanced proprioceptive feedback and reduced fall risk.

Overall, both exercise modalities effectively enhance functional fitness in older adults. Given its low-impact and proprioceptive advantages, aquatic exercise offers a safer alternative for individuals with balance or musculoskeletal challenges. Incorporating targeted resistance training may optimize gains in specific domains such as grip strength. Future research should explore combined aquatic-land programs to maximize functional improvements.

The study exhibits several methodological strengths. Its experimental design allows for causal inference, while the implementation of multicomponent, standardized protocols across aquatic and land-based settings enhances both comparability and intervention fidelity. Comprehensive outcome measures encompassing strength, balance, flexibility, agility, and endurance afford a robust, multidimensional assessment of physical function. Adherence was supported through reminder calls and make-up sessions, further strengthening study rigor.

However, certain limitations warrant consideration. The sample consisted solely of older women with a modest size, limiting the generalizability of findings. The eight-week intervention period restricts conclusions regarding long-term effects. Participant blinding was unfeasible, and potential confounding factors such as diet, medication, and baseline activity levels were uncontrolled. Moreover, important domains including psychological, cognitive, and quality-of-life outcomes were not evaluated. This study also lacked assessment of participants’ subjective perceived effort and did not monitor weekly progression; incorporating such measures (e.g., Borg Rating of Perceived Exertion scale) in future research could yield valuable insights into motivation, adherence, and program feasibility. Finally, attrition and the absence of per-protocol analyses may have introduced bias. Future investigations should prioritize extended follow-up durations, gender-balanced cohorts, and a broader range of outcome variables to support the development of more comprehensive and sustainable intervention strategies.