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INTRODUCTION
The growing worldwide population of elderly individuals can be attributed to advancements in healthcare. The aging process leads to the decline of the somatosensory, visual, and vestibular systems responsible for maintaining balance [1]. Additionally, the functional capacity of all bodily systems declines, increasing the likelihood of a high risk of falls [2]. Falls prevention among older people is an important global public health concern. The majority of falls among older people occur while walking [3,4]. The second most common cause of mortality from non-intentional injuries worldwide is falls, and research indicates that 40% of community-dwelling seniors aged 65 and over experience falls annually [5]. Physical inactivity and functional ability deficits, such as compromised balance and decreased lower limb muscular strength, have been recognized as autonomous factors that contribute to falls and fall-related injuries, including head injuries and hip fractures, in the elderly population [6,7].
Several studies have shown a correlation between impaired stepping ability and falls among older individuals [8-10]. Multi-directional steps are essential for activities of daily living (ADL) because, while walking indoors, 35%–50% of all steps consist of those that change the direction of movement, i.e., non-straight steps [11]. Normal individuals should be able to take steps in multiple directions to perform ADL safely. Previous studies have shown that step training with multiple directions has been shown to enhance balance and walking ability in elderly individuals and those diagnosed with Parkinson’s disease [12-14]. The square step-up training, in which patients perform step-up exercises in many directions on a box, enhanced lower extremity strength and balance ability more than the general walking exercise group [15]. A more specific form of balance training for fall prevention is step training. A recently published meta-analysis by Okubo et al. [16] found that volitional and reactive step-up training can remarkably reduce fall rates by 50%. Training elderly women to perform bench steps with increasing step heights simultaneously enhances their functional capacity, thigh strength, and force-velocity characteristics of the knee extensors [17]. This exercise pattern also improves lower body strength, balance, and agility in the elderly. Besides, this exercise is an aerobic exercise and, thus, can improve cardiorespiratory fitness [18]. For exercise adherence, the evidence indicates that this exercise, as a dichotomous approach, provides a practical, time-efficient, and low-threshold program for the elderly. This activity offers many advantages simultaneously by using a dichotomous strategy.
Compared to training methods conducted on a stable support surface, functional training with unstable support is advantageous for increasing exercise difficulty due to the induction of unexpected proprietary sensory information and reaction forces in multiple directions [19]. A further study demonstrated that exercising on foam and sand improves this system’s function due to the proprioceptive system’s involvement, increases ankle strength and improves sensory information processing in sudden perturbations. Moreover, previous studies reported the effects of unstable surfaces [20,21], but overall improvements in lower-extremity muscle strength, power, and balance were similar. A practical and safe alternative training program to mitigate intrinsic fall risk factors in older adults [22,23].
Some previous studies have demonstrated the effectiveness of step-up training in enhancing functional activity, gait, and balance across various patient populations. However, insufficient studies have applied combining stepping exercises in various directions on unstable or uneven surfaces simultaneously. Therefore, this study aimed to compare the effects of modified stepping exercises on an unstable surface for 6-weeks on overall physical function, including walking, functional strength of lower limbs, and balance ability in community-dwelling older individuals.
METHODS
Study design and setting
This randomized controlled was condunted in rural community and sub-district health promotion hospitaltrial Phayao, Thailand. Complies with the CONSORT (Consolidated Standards of Reporting Trials) guidelines statement for transparent reporting, which was registered in the Clinical trail NCT06505083. The study protocol was approved by the Human Research Ethics Committee at the University of Phayao Review Board (protocol code: HREC-UP-HSST 1.2/101/66; approval date: 8/06/2023). Before participating in any study-related procedures, each participant provided informed consent by signing a consent form. To protect participants’ privacy, each record in the database was assigned a unique alphanumeric code. The study was conducted by the principles outlined in the Declaration of Helsinki.
Participants
Participants were recruited from a local community in Thailand between June 2023 and March 2024. Eligibility criteria included age 65 years and older, absence of regular exercise (defined as twice per week for one week), willingness to understand the study purpose and procedures accurately, and voluntary participation. Additionally, eligible participants were required to walk over at least 10 m without assistive devices independently, and the participants who demonstrated a single leg stand (SLS) test duration of less than 10 seconds indicated a higher predictive fall risk among older adults [24]. Exclusion criteria encompassed individuals exhibiting signs or symptoms that might impede walking or study participation, such as unstable medical conditions, inflammation in the lower extremity joints (with a pain scale rating of more than 5 out of 10 on a visual analog scale), and sequelae of neurological deficits. Participants diagnosed with dementia, depression, severe cardiovascular disease, or mental illness were also excluded. Moreover, the included participants did not have confirmed dementia and attained a total score of 24 or more on the Thai version of the Mini-Mental State Examination.
Ultimately, 32 participants who fully comprehended the study’s purpose and content and consented to participate were selected as target participants (Fig. 1). Participants were randomly allocated to either the experimental group (n=16), undergoing unstable stepping exercises, or the control group (n=16), engaging in stable stepping exercises, utilizing a computer-generated permutation block randomization design. The design of this study is a single-blind, randomized controlled trial (subjects blind). All data were measured by the same physical therapist before, after the 4-week, after the 6-week intervention and 1 month follow-up. Detailed study explanations were provided to all participants, and written informed consent was obtained before their involvement. Participants were assured of their right to withdraw from the study at any time. Demographic characteristics, including weight, height, age, and sex, were collected through participant interviews, and body mass index (BMI) was calculated using the formula: BMI=weight (kg)/height (m)2.
Sample size
The sample size estimation was based on an effect size of treatment measured with the Timed Up and Go test (TUGT) of 8.1 seconds for people with elderly [25]. The analysis was based on a one-sided paired t-test at 80% power with a significance level of 0.025, 12 participants per group are needed. Considering a 20% dropout rate, the sample size of 16 participants per group was estimated using G*Power 3.1.
Experimental procedure
The training in the modified stepping exercise both groups had three components; a 10-minute warm-up and stretching session, a 30-minute session of modified stepping exercise (The exercise program was divided into two phases. Participants were required to exercise continuously for 15 minutes, followed by a rest period of no more than 5 minutes. They then resumed exercising for another 15 minutes. This cycling was maintained for three weeks. From weeks 4 to 6, participants were instructed to exercise continuously for 30 minutes without taking any breaks between sessions), and a 10-minute cool-down with stretching to reduce exercise fatigue and prevent accidents. To achieve the desired level of intensity for this exercise, it is recommended to use a modular approach similar to resistance training, namely at 60% of the one-repetition maximum [17,25]. The research used the Aroma Mechanic Metronome model AM-707 BK, which operates at a tempo of 80 beats per minute (bpm), to control each of the participants’ rhythmic frequencies. However, no guidelines are available about the number of bench-stepping repetitions required to achieve hypertrophy and strength gains. Therefore, we selected the number of repetitions based on previous studies using multi-joint resistance exercises such as the leg press [26]. The intervention program for both groups involved performing step-up on a wooden box with dimensions of 45 cm×30 cm×18 cm. For the experimental group, foam pads with a thickness of 2 inches (45 cm×30 cm×16 cm) were added to the step box, creating a soft, unstable surface for step-up training (Fig. 2). In contrast, the control group performed step-up directly on a wooden box of the same size, providing a stable, firm surface for training. The step-up exercise was performed three times per week for six weeks, totaling 18 sessions. The detailed, multi-directional step-up training procedure was as follows: Participants performed step-up and step-down movements in three directions: forward, right side, and left side. They were instructed to step onto and off the box at a consistent speed during each trial. Each participant was closely monitored throughout the training sessions by a physical therapist to ensure proper technique, provide support, and minimize fatigue or errors. Adequate rest periods were provided between trials. The participants from each group conducted their exercise programs in separate villages under the supervision of a physical therapist.
Outcome measures
Participants had an evaluation of their functional mobility, which is essential for achieving independence, including the TUGT, Five Times Sit-to-Stand test (FTSST), 10 Meter Walk Test (10MWT), and individual muscle strength: hand-held dynamometer, and back-leg-chest test in a random sequence by a group of assessors who had excellent inter-rater reliability (intraclass correlation coefficients [ICCs]=0.88–0.99). The measurements were executed three times, including before training (pre-test), after 4-week training (intermediate test), after 6-week training (post-test), and after one month (follow-up).
Measurements
TUGT
The study participants were instructed to sit on a chair (46 cm height) without an armrest [27]. They were instructed to get up from the chair on command, walk at a comfortable pace, walk around the cone marked 3 m ahead, and return to a seated position on the original chair. The stopwatch was started as soon as the paticipants lifted their buttocks off the chair, and it was stopped at the point where the paticipants sat back in the chair after completing walking. The total time each paticipants took to complete the task was noted as the final score [28].
FTSST
The FTSST is a simple and quick test initially designed to be a proxy measure of lower-limb strength. The test requires a paticipants to stand up and sit down five times as quickly as possible from a chair with a seat 43 cm high. The time taken to complete the test (the FTSST scores) is recorded with a stopwatch. Excellent test-retest reliability of FTSST scores (ICC=0.933) has been reported in people with chronic stroke and community-dwelling older adults (ICC=0.89–0.96). Several other studies have demonstrated the reliability or validity or both of FTSST scores in specific paticipants populations, including Parkinson’s disease [29] and renal pathologies and participants with rheumatoid arthritis and balance disorders [30].
10MWT
The 10MWT was used to evaluate gait ability. This test generally evaluates the gait velocity of patients with neurological damage and shows high inter-rater and intra-rater reliability (r=0.89–1.00) [31]. In the present study, the paticipants were instructed to individuals perform three 10-m overground walk trials timed with a stopwatch in each comfortable and maximum speed to characterize our participant sample. For comfortable walking speed, individuals were instructed to “walk at a speed that feels the most comfortable,” and for maximum speed, individuals were instructed to “walk at the fastest speed you feel safe” walk 10 m; the time taken for 4 m, excluding the first 3 m and the last 3 m, which take into account acceleration and deceleration, was measured in units of seconds [28].
Individual isometric muscle strength
The strength of maximum isometric voluntary contraction of the paticipants’s hip flexor, extensor, adductor, abductor, knee flexor, extensors, and ankle dorsiflexion, plantar flexors (in kilograms) was measured using a Nicholas handheld dynamometer (HHD) (model 01,160; Lafayette Instrument Company). The Nicholas HHD is a digital force gauge measuring forces from 0.0 to 199.99 kg. The measurement protocol was described by Magalhães et al. [32]. The make test, operationally defined as a maximal effort exerted against a stationary HHD, was used to quantify the isometric force production. For the knee flexors and extensors, the participants were seated in a high chair with hip and knee flexion fixed at 90°, and the dynamometer was placed on the anterior aspect of the tibia at 5 inches proximal from the tip of medial malleoli. The portable dynamometer was positioned across the medial and lateral malleolus of the foot to measure the strength of the hip adductor and abductor muscles. In this position, participants were lying supine on a yoga mat. During the test, the examiner manually stabilized the body parts proximal to the tested limb segment. The participants assumed the prone position on a yoga mat while the researcher positioned a hand heal dynamometer at the posterior ankle joint to assess the hip extensor and knee extensor. The individuals were lying supine on a yoga mat while their ankle dorsiflexors and plantar flexors were assessed. The portable dynamometer was positioned on either the top or bottom side of the foot, specifically above the metatarsophalangeal joint. During the test, the examiner manually stabilized the body parts proximal to the tested limb segment. The participants assumed the prone position on a yoga mat while the researcher positioned a hand heal dynamometer at the posterior ankle joint to assess the hip extensor and knee extensor. Each paticipants completed three trials in which maximal force was generated for 2–3 seconds in three actions with each leg testing. A 5-minute rest interval was inserted between each measurement. A composite leg strength score was calculated by dividing the mean left and right-side strength score (mean scores in the three actions, divided by 2) by body weight (kg). The average value of three trials was used for data analysis [33].
Back-leg-chest dynamometer
A calibrated back-leg-chest dynamometer (BLCD) (the Takei 5402 Back Muscle Digital Dynamometer) measures isometric muscle strength, recorded in kilograms of force. There is excellent test-retest reliability (ICC=0.98) for leg extension strength [34]. The dial ranges from 0 to 300 kg (0 to 660 lb) in 10 kg (10 lb) increments. For the test, the length of the chain was adjusted to the participants’ height by asking the paticipants to stand on the base of the BLCD with extended knees. Subsequently, the handle was positioned at the height of the intra-articular space of the knee joint. For the test, participants had to stand on the base, with knees and hips flexed slightly, while the lower back had to maintain an appropriate lordotic curve. Participants were asked to lift in a vertical direction by providing continuous isometric contractions of the knees, hips, and lower back extensors while holding the handle. Participants were asked to increase the pull safely gradually and reach the maximal force in three seconds while keeping this pull for another two seconds. After the demonstration and a familiarization trial, three trials were performed, with rest periods of 30 seconds between trials [35]. The maximal strength for the three trials was used for further analysis.
Statistical analysis
Descriptive statistics were used to describe the participants’ demographics and the study’s findings. The Shapiro-Wilk test was used to verify the normality of the acquired data. Independent t-tests (for continuous data) and chi-square tests (for categorical data) were used to determine differences between the intervention and control groups at baseline. A 4×2 mixed-model ANOVA, with time (pre-test, 4-week, 6-week, and 1 month follow-up) as a within-subjects vaiable and group (soft-surface stepping and firm-surface stepping) as a between-subjects variable, was used to analyze the effects of interventions on the outcome meaures and to identify significancant group-by-time interactions. Significant interction effects were compared using post hoc Bonferroni pairwies comparison. To determine the effect size of the time×group interaction, the partial eta squared (ηp2) was calculated, which was interpreted considering the ηp2 values of 0.01, 0.06, and 0.14, which correspond to effect sizes small, moderate, and large, respectively. The level of significant difference was set at a p-value of <0.05. Analyses were performed with SPSS (version 29 for Windows; IBM Corp.).
RESULTS
Baseline participant characteristics and adherence
A total of 32 participants were divided equally into an experimental group of 16 people and a control group of 16 participants. Table 1 provides a concise summary of the key characteristics of the research participants. There were no significant differences in the sex, age, body weight, height, BMI, and vital sign features of the participants through the groups at the beginning of the study (p>0.05). The training sessions had a 90% attendance rate, and all participants completed their allocated progression program.
Functional and walking ability
Significant within-group improvements in functional outcomes were observed in the soft-surface stepping exercise group, specifically in TUGT, BLCD, and FTSST at week 4, week 6, and the one-month follow-up (TUGT: F₃,₁₃=5.12, p=0.015; BLCD: F₃,₁₃=21.94, p<0.001; FTSST: F₃,₁₃=22.75, p<0.001, respectively). Conversely, the firm-surface stepping exercise group showed significant within-group improvements in TUGT and FTSST only at week 6 and the one-month follow-up (TUGT: F₃,₁₃=6.56, p=0.006; FTSST: F₃,₁₃=8.22, p=0.003). Additionally, BLCD significantly improved in both groups at week 4 and week 6; however, no significant improvement was observed at the one-month follow-up in the firm-surface stepping exercise group (F₃,₁₃=8.00, p=0.003). Regarding walking speed, the 10MWT showed significant improvements only at week 6. In the soft-surface stepping exercise group, both preferred (F₃,₁₃=4.11, p=0.029) and fast walking speeds (F₃,₁₃=3.51, p=0.046) improved significantly. Similarly, in the firm-surface stepping exercise group, significant improvements were observed in both preferred (F₃,₁₃=3.78, p=0.038) and fast walking speeds (F₃,₁₃=4.68, p=0.020) (Table 2). The between-group analysis (time×group interaction) revealed that the soft-surface stepping exercise had a large effect size on the TUGT (ηp²=0.140, p=0.035) and leg muscle strength (BLCD) (ηp²=0.182, p=0.015), indicating greater improvements in balance ability and lower limb muscle strength compared to the firm-surface stepping exercise group after the 6-week intervention. However, no significant differences were observed for the FTSST and walking speed (10MWT) (Table 2).
Isometric muscle strength
Participants in the soft-surface stepping exercise group demonstrated significant improvements in muscle strength across multiple muscle groups, including the hip extensors (F₃,₁₃=12.56, p<0.001), hip adductors (F₃,₁₃=14.07, p<0.001), hip abductors (F₃,₁₃=32.37, p<0.001), knee extensors (F₃,₁₃=84.13, p<0.001), ankle dorsiflexors (F₃,₁₃=16.27, p<0.001), and ankle plantarflexors (F₃,₁₃=8.05, p=0.003) from baseline (pre-test) to 4 weeks, 6 weeks, and one month post-intervention (p<0.05). Notably, significant changes were observed between 4 and 6 weeks in the hip extensors, hip adductors, hip abductors, and knee extensors (p<0.05) (Table 3). Additionally, ankle plantarflexor strength significantly increased between 6 weeks and the one-month follow-up (p<0.05). Furthermore, significant improvements in hip flexor and knee flexor strength were observed after 6 weeks of intervention (F₃,₁₃=17.09, p<0.001 and F₃,₁₃=21.36, p<0.001, respectively). The firm-surface stepping exercise group showed significant improvements in muscle strength from baseline to 6 weeks and one month post-intervention in the hip flexors (F₃,₁₃=5.83, p=0.009), hip extensors (F₃,₁₃=8.43, p=0.002), hip abductors (F₃,₁₃=6.11, p=0.008), knee flexors (F₃,₁₃=18.93, p<0.001), ankle dorsiflexors (F₃,₁₃=16.06, p<0.001), and ankle plantarflexors (F₃,₁₃=5.94, p=0.009) (Table 3). While the knee extensors (F₃,₁₃=26.70, p<0.001) showed significant improvements from baseline to 4 weeks, 6 weeks, and one month post-intervention, the hip adductors showed a trend toward significance (F₃,₁₃=3.10, p=0.064). Additionally, significant improvements in ankle dorsiflexor strength were observed between 4 and 6 weeks (p<0.05) (Table 3).
The 4×2 mixed-model analysis of variance revealed a significant time×group interaction for hip flexors (approximately 2 kg, ηp²=0.122, p=0.041), hip extensors (ηp²=0.126, p=0.047), hip adductors (ηp²=0.155, p=0.026), and hip abductors (ηp²=0.127, p=0.046), indicating greater improvements in isometric lower limb muscle strength in the soft-surface stepping exercise group compared to the firm-surface stepping exercise group after the 6-week intervention. However, no significant time×group interactions were observed for knee flexors, knee extensors, ankle dorsiflexors, or ankle plantarflexors (p>0.05) (Table 3).
DISCUSSION
This study explored the effectiveness of modified stepping exercises with soft and firm surfaces for six weeks to improve older elderly on parameter of muscle strength, gait, balance ability, and lower extremity muscle strength. The results of this study indicate significant within-group improvements in functional performance and muscle strength following the intervention, with significant changes observed at weeks 4, 6, and the one-month follow-up (p<0.05) in both the soft-surface and firm-surface stepping exercise groups. However, the group×time interaction analysis revealed that the soft-surface stepping exercise group exhibited a large effect size on both the TUGT and BLCD, as well as on hip flexor, hip extensor, hip adductor, and hip abductor strength. The results of thisstudy suggest that the soft-surface group experienced greater improvements in balance and lower limb muscle strength compared to the firm-surface group after 6 weeks of intervention.
To the best of our knowledge, this is the first study to demonstrate the effectiveness of soft-surfac stepping in improving balance and overall muscle strength in elderly. Stepping exercise is a conveniently dynamic cardiovascular workout. It is safe with no adverse consequences and enhand to improve physical fitness among older adults after 12 weeks of training [36,37]. Our data confirm the benefits of a modified stepping exercise with a soft surface, demonstrating its effectiveness in improving balance ability and overall muscle strength after just four weeks of training. In the present study, participants who underwent soft-surface stepping exercise training demonstrated significant improvements in balance ability, as measured by the TUGT, compared to those in the firm-surface stepping exercise group. Notably, the soft-surface group showed significant improvements within 4-weeks, with continued progress observed at six weeks and the one-month follow-up. The effect size (η²) for the TUGT was 0.140 lage effect sizes. In contrast, participants in the firm-surface stepping exercise group exhibited significant improvements only at 6-weeks and the one-month follow-up. Moylan and Binder [38] reported that the movement of step-up during alternate single leg step up-down and lateral up-down would help to improve coordination of lower limbs and anticipatory postural adjustments of motor planning during multidirectional steps to maintain the body’s center of gravity on unstable or soft surfaces. In addition, the repetitive stepping exercise with various dynamic stepping patterns would also enhance proprioception (the sense of body position in space) [38,39]. Kaewjoho et al. [23] reported that a six-week Thai dancing intervention performed on a soft surface significantly improved balance ability in healthy older adults compared to exercises performed on a firm surface. Therefore, soft surface stepping exercise had greater improvement at within 6 weeks afer training. Previous studies have shown that stepping exercises can improve physical performance, particularly balance abilities in the elderly, after an extended duration of 8 weeks of exercise [39]. Accoding to Sarinukul et al. [25] reported that eight weeks of stepping exercise improved TUGT and quality of life in healthy elderly paticipants, in which significant improvements from baseline were also evident at 8 weeks. A key strength of this study is the observed mean TUGT improvement of 2.34 seconds, which is clinically meaningful for older adults at high risk of falls, as indicated by an SLS test duration of less than 10 seconds. This improvement surpasses the established threshold for a meaningful reduction in fall risk, underscoring the practical relevance of our intervention despite the statistical limitations imposed by multiple comparison corrections.
However, the participants in these earlier studies were healthy adults, while the majority of participants in this study were older adults with a higher fall risk (as indicated by a SLS test result of less than 10 seconds). It is anticipated that the older adults in this study may show greater improvements than their healthy counterparts due to the higher fall risk at baseline. The within-group analysis in this study showed that walking speed, both preferred and fast speeds, demonstrated greater improvements in the soft-surface stepping exercise group at 6-weeks and one month after training. These improvements may be attributed to the enhanced range of motion and increased torque generation in the lower limb, which contribute to better walking speed efficiency. According to Mansfield et al. [40] reported that step box training serves to augment the deficiencies of stair walking training. Utilizing a step box for stepping training is purportedly beneficial in enhancing muscle mass in the paralyzed lower limbs of stroke patients, as well as improving walking speed [41] and balance. In particular, walking on an unstable support surface such as a balance pad requires more muscle strength and movement around the ankle joint, thereby improving walking speed.
Furthermore, in the present study, overall lower limb muscle strength, as measured by the BLCD, demonstrated meaningful improvements a large effect size (η²=0.182), while individual muscle groups showed large effect sizes (η²=0.122 to 0.155) when assessed using HHD. These results indicated significant improvements in the soft-surface stepping exercise group. Specifically, participants exhibited greater strength gains in the hip flexors, hip extensors, hip adductors, and hip abductors, with these improvements becoming particularly pronounced at the six-week mark in between-group comparisons. However, no significant differences were observed between the groups for knee flexors, knee extensors, ankle dorsiflexors, or ankle plantarflexors. The stepping exercise involves several phases: the initial step-up (concentric phase), mid-step-up (isometric phase), and step-down (eccentric phase). During the initial step-up, hip flexors, such as the iliopsoas and rectus femoris, are activated concentrically to lift the leg toward the box. The iliopsoas primarily serves to flex the hip and raise the thigh, while the rectus femoris plays a role in both hip flexion and knee extension. In the mid-step-up (isometric phase), the hip flexors, including the iliopsoas, work isometrically to maintain the flexed position of the hip and stabilize the thigh against gravity as the body is positioned on the box. Meanwhile, the hip extensors, such as the gluteus maximus and hamstrings, contract isometrically to keep the hip extended and stabilize the pelvis. The gluteus maximus ensures the upright posture, while the hamstrings contribute to maintaining proper alignment of the knee and hip. During the step-down (eccentric phase), the hip extensors, including the gluteus maximus and hamstrings, work eccentrically to control hip flexion as the body lowers toward the ground. These muscles prevent excessive hip flexion and help stabilize the pelvis during the descent.
Hip abductors (gluteus medius), the gluteus medius plays a critical role in stabilizing the pelvis during the step-up and lateral stepping movements. It helps prevent the pelvis from dropping on the opposite side when standing on one leg. In stepping down or lateral movements, the abductor muscles contract eccentrically to control pelvic tilt. Hip adductors, these muscles also stabilize the lower body and help in controlling movement during stepping, particularly in preventing excessive lateral motion of the pelvis. The hip adductors contract during stepping to bring the legs closer together and maintain proper alignment during dynamic movements [42]. In addition, the repetitive stepping training on unstable or soft surfaces would challenge the muscles involved during stepping training. This study modified stepping exercises to include various directions, such as step-up and step-down movements, along with left and right lateral step-up and step-down motions. The findings suggest that soft unstable, multidirectional stepping exercises are beneficial for improving overall lower limb muscle strength and coordination and muscle activation. The continuous adjustments made by the body during exercises on an unstable surface enhance motor control, improve muscle recruitment, and increase the overall muscle strength response, even after just 4 weeks of training. This mechanism has been supported by previous studies on balance and strength training on unstable surfaces, which suggest that the requirement for constant adjustments during movement promotes greater muscle engagement and neuromuscular adaptations compared to stable surfaces. Worrell et al. [43] reported that step training enhances isokinetic extensor muscle strength in healthy participants.
Comparing the outcomes of the soft surface stepping exercise group with the firm surface stepping exercise group revealed that the soft surface stepping exercise experienced greater improvements in balance ability, walking speed, and muscle strength during weeks 4–6, with these benefits persisting over time. One month follow-up, participants in this group maintained their balance ability and lower limb strength, hese sustained improvements can be attributed to the repetitive movements that enhance muscle strength, coordination, and proprioception, particularly in response to balance perturbations, resulting in quicker and safer movements during the test. Additionally, the involvement of the extensor and flexor muscle groups during sagittal plane stepping, as well as the adductor and abductor muscles during coronal plane movements, is further challenged by the unstable terrain. To confirm the effects of the soft-surface stepping exercise, a subsequent study should include a control group with no intervention, alongside implementing a randomized controlled trial design. This would allow for a more rigorous comparison and enable the assessment of recruitment and retention rates. Additionally, it would be beneficial to assess the prevalence of chronic conditions, including hypertension, diabetes, dyslipidemia, and cardiovascular diseases, as well as participants’ history of falls in the 12 months prior to the study. This study is the small sample size, which may have resulted in insufficient statistical power to detect significant between-group differences. Although clinically meaningful improvements were observed, future studies with larger sample sizes are recommended to confirm these findings. Further investigation is also recommended to monitor the incidence of falls one year following the completion of the intervention, in order to better understand the long-term effects of the program.
Conclusions
Soft surface stepping exercise are comparable in perceived intensity to basic exercises, and they are moderate-intensity exercises after undergoing the program for six weeks (3 times/40–50 minutes/weeks) that increase recruitment and retention rates after the intervention program. The intervention significantly improved the participants’ functional mobility, walking ability, and lower extremity muscle strength within 4-weeks and significantly increased their overall health status. Hence, the present findings suggest that using soft surface stepping exercise program might be a practical approach to enhance independence and security among community-dwelling older adults.
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