Progressive Strength and Balance Exercise for Fall Prevention in Postmenopausal Women With Osteoporosis

Postmenopausal osteoporosis is associated with an increased risk of fragility fractures, functional decline, disability, and loss of independence. Falls are a major modifiable pathway leading to fragility fractures in older adults. Exercise-based fall-prevention strategies, particularly those including balance and resistance training, may improve muscle strength, postural control, gait performance, and confidence during mobility. However, evidence remains limited regarding structured progressive exercise programs specifically evaluated in postmenopausal women with osteoporosis in clinical rehabilitation settings.

This study was designed as a single-center, single-blind, randomized, parallel-assignment pilot trial conducted in postmenopausal women with osteoporosis. The objective was to evaluate the effects of a supervised progressive strength and balance exercise program on fall occurrence and fractures compared with a conventional home-based exercise program. A secondary objective was to explore whether baseline functional measures, including balance performance and handgrip strength, were associated with fall occurrence during follow-up.

Eligible participants were postmenopausal women aged 60 to 80 years with osteoporosis confirmed by dual-energy X-ray absorptiometry, defined as a T-score <= -2.5 at the lumbar spine, total hip, or femoral neck. Participants were recruited from the Osteoarticular Rehabilitation Service of the Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Mexico City, Mexico. The protocol was initiated in 2019; however, study activities were suspended during the COVID-19 pandemic. The final analyzed sample consisted of 46 participants recruited consecutively by convenience sampling between 2023 and 2025.

After baseline assessment, participants were randomly allocated to either the supervised progressive strength and balance exercise program or the home-based conventional exercise program. Randomization was performed using a random-number table, and allocation was concealed using opaque, sealed, sequentially numbered envelopes that were opened after completion of baseline assessment. Outcome assessments were performed by an evaluator blinded to group allocation. Participants and treating therapists could not be blinded because of the nature of the exercise intervention.

Participants in both groups were instructed to perform home exercises three times per week, with each session lasting approximately 60 minutes, for 6 months. Adherence of at least 80% of prescribed sessions was considered adequate. Before starting the exercise program, anteroposterior and lateral thoracolumbar and sacral spine radiographs were obtained to identify asymptomatic vertebral fractures. Incident fractures during follow-up were corroborated by available clinical imaging, including radiography or computed tomography.

The experimental intervention consisted of an initial supervised institutional training phase followed by a home-based progressive program. The supervised phase included 10 sessions delivered Monday to Friday over two consecutive weeks. During these sessions, participants were taught how to perform and progress each component of the program. The intervention included progressive resistance training, core stabilization exercises, and balance exercises.

For resistance training, the 10-repetition maximum load was estimated during the first three training days. Participants performed three sets of 10 repetitions using this load. Every four weeks, either the number of repetitions or the load was increased. When repetitions were increased, participants progressed to 12 repetitions using the same load; when load was increased, repetitions returned to 10. Load increments were 0.25 kg until reaching 2 kg and 0.5 kg thereafter.

Core stabilization exercises were performed in five positions: standing, sitting, supine, anterior bridge, and lateral bridge. During the first month, exercises were performed in supine, sitting, and standing positions. The anterior bridge was added at the first follow-up visit, and the lateral bridge replaced sitting and standing positions at month 3. Contractions were initially held for 10 seconds and progressed by 5 seconds each month up to 30 seconds.

Balance training followed a 14-level progression including feet-together standing, alternating weight transfer, lateral walking, single-leg stance with hand support, semi-tandem stance, toe walking, heel walking, cross-over lateral walking, single-leg stance without arm support, tandem stance, single-leg stance while passing a cushion around the body, tandem walking, single-leg stance on a cushion, and backward tandem walking. Participants performed four balance exercises at home, and difficulty was progressed at follow-up visits according to exercise mastery.

The control group received one individual 60-minute instructional session and a printed home-exercise sheet with the conventional program used by the service. This program included postural correction exercises, static single-leg balance, balance on an irregular surface, dynamic balance exercises, and initial stabilization exercises in supine and anterior bridge positions. Unlike the experimental program, the control intervention did not include planned progression of exercise difficulty.

Follow-up visits were scheduled at 1, 3, and 6 months. At each visit, adherence to home exercise was assessed, falls and fractures were ascertained, and the exercise program was reinforced in both groups. In the experimental group, exercise progression was also recorded and higher-difficulty exercises were taught when appropriate. Participants received adherence sheets to record the sessions performed and any fall or fracture events, and these sheets were collected at follow-up visits.

The primary outcome was the proportion of participants with at least one fall during the 6-month follow-up period. A fall was operationally defined as any involuntary, accidental, and non-intentional event in which the participant, while standing, walking, sitting, or performing a usual activity, lost balance, tripped, slipped, or descended suddenly to the ground, floor, or a lower surface, from a height equal to or lower than her own stature, without a high-energy mechanism. Events due to motor-vehicle accidents, being struck by a vehicle, falls from stairs, roofs, scaffolds, bicycles, motorcycles, elevated beds or chairs, physical aggression, high-impact sports, crushing mechanisms, or any other high-energy mechanism were not considered falls from standing height or lower.

Secondary outcomes included incident fragility fractures, functional performance, balance, balance confidence, handgrip strength, gait speed, posturography parameters, adherence to the intervention, and exercise-related adverse events. Functional assessment included the Timed Up and Go test, Berg Balance Scale, Activities-specific Balance Confidence Scale, handgrip strength, gait speed, and posturographic variables. Exploratory analyses evaluated whether baseline functional thresholds, including Berg Balance Scale score <53 points and maximum handgrip strength <20 kg, were associated with fall occurrence during follow-up.

Because this was a pilot trial, no formal sample-size calculation was performed. The sample consisted of consecutively recruited eligible participants included by convenience. The study was intended to generate preliminary estimates of intervention effects, evaluate feasibility and safety, and support the design of future adequately powered randomized trials in postmenopausal women with osteoporosis.

This ClinicalTrials.gov record represents retrospective registration of a completed single-blind randomized controlled pilot trial. Participant enrollment and 6-month follow-up were completed before initial submission of this registration. The protocol was approved before study conduct by the institutional research and ethics committee of the Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra under approval number 126_4-R. Registration was completed retrospectively during manuscript preparation to provide a public record of the study design, interventions, outcomes, and data sharing plan. The reason for delayed registration was due to administrative delay during study restart and completion after COVID-19-related suspension of study activities. . All study status, enrollment, and study dates are reported as actual.