Effects of High-Intensity Interval Training on Bone Health in Hong Kong Older Women

Hong Kong Baptist University48 enrolled

Overview

Osteoporosis is an age-related disease, characterized by a decreased bone mass and an increased risk of fragility fractures. Osteoporosis leads to increasing mortality, disabilities, morbidity of chronic pain, and the cost of health and social care, as well as decreasing the quality of life from reduced independence and hindered physical, mental, and social well-being. A recent review and meta-analysis, investigating the association between physical activity and osteoporosis prevention in elderly people, indicated that the traditional exercise interventions (i.e., resistance training) were undertaken for 60+ mins, 2-3 times/week for 7+ months. However, participation rates remain low in these exercise programs among older adults, in part due to a need for specialized equipment and correct techniques to prevent injury. In addition, low motivation and associated compliance with such conventional exercise is problematic among older adults. Considering there is little evidence of HIIT benefits related to older women with osteopenia, the current study aims to evaluate the effectiveness of a 24-week HIIT intervention on bone mineral density, bone turnover markers and other health-related outcomes among Hong Kong Chinese older women.

The study will be a randomized controlled trial (RCT) with two groups and three times repeated measures. Data will be collected in a pretest, post-test, and six months after the intervention. The eligible participants will be randomly distributed into one of two groups in a ratio of 1:1. The participants recruited and meeting the screening criteria will receive a 24-week HIIT intervention or recreation workshop. The intervention effects will be evaluated on bone mineral density, bone turnover markers, physical fitness, fear of falling, and quality of life.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Enrollment

Interventions

HIIT program for 24 weeks with a frequency of 2 times per week.BEHAVIORAL

Participants will receive a 24-week HIIT program, with 2 sessions per week. Each session will comprise three sections, including warm-up, main exercise and cool down. The time will be between 37 to 40 minutes with progression of training. Each HIIT section will include six high-impact weight-bearing exercise. For Weeks 1-4, the HIIT section will include 12 intervals of 30 seconds HIIT workout at corresponding intensity, separated by 11 intervals of 60 seconds of active recovery. To ensure the subjects' safety, a chair will be used for assistance during training in the first month. Additionally, a 3 kg weight will be incorporated for the training in the final two months.

Non-exercise controlBEHAVIORAL

Workshop participants in the non-exercise control group will receive a series of workshops related to daily recreation.

Eligibility

Sex: FEMALEMin age: 60 YearsMax age: 74 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * • 60 to 74 years at the start date of the project * diagnosed with osteopenia by DXA scan screening with a BMD at the femoral neck or total hip or lumbar spine between -1 and -2.5 SD T-score below the average values * Passing the PAR-Q plus screening or with the physician's approval for readiness to participate in high-intensity exercise * Above the average level of 2-mins stepping showing competent aerobic fitness * No restriction on physical mobility * No cognitive impairment, as determined by the Chinese version of the Mini-Mental Status Examination (i.e., score \< 24) * No previous substantial experiences in practicing HIIT. The written informed consent form will be collected from each participant Exclusion Criteria: * • Severe chronic disease restricting high-intensity exercise * Having cognition impairment regarded by specialists * checked through medical records at HA Go app platform in the past 6 months, have concurrent medical conditions (e.g., thyrotoxicosis or hyperparathyroidism, Paget's disease, renal disease, diabetes, knee or hip osteoarthritis) and use medications (e.g., corticosteroids, estrogen, thyroxine, thiazide diuretics, or antiretroviral agents) known to affect bone metabolism during past 2 years * any condition with osteoporosis, osteoporotic fractures * current smoker * alcohol 3 or more units per day.

Outcomes

Primary Outcomes

Bone mineral density

Bone mineral density at the non-dominant lumbar spine and femoral neck of hip will be measured by one registered technician using DXA (XR-46, Norland, Wisconsin, USA) at an assessment center in the Chinese University of Hong Kong.

Time frame: Outcome evaluations will be performed three times at pre-intervention (T1 baseline), after 24-weeks intervention (T2 post-test), and 6 months after intervention completion (T3 follow-up test).

Bone turnover markers

The two bone turnover markers, P1NP (ng/ml) and CTX (ng/L) will be used to assess the subjects' bone formation and bone resorption. Participants must arrive at the elderly center between 08:30 and 09:30 a.m. after a 12-hour overnight fast and avoid intense physical activity the night before. A qualified nurse will collect 5 mL of venous blood from the antecubital vein, which will coagulate at room temperature for 20-30 minutes before being transported to the lab within one hour. The blood will then be centrifuged at 4 °C and 3000 rpm for 50 minutes, with the resulting sample stored at -80 °C for serum biochemical marker assays. Serum P1NP and CTX levels will be measured using ELISA kits from Immunodiagnostic Systems Inc., and analysis will be conducted by the Hong Kong Polytechnic University test lab.

Secondary Outcomes

Physical fitness_Body mass index

BMI (kg/m²) was calculated by dividing weight in kilograms by the square of height in meters. Body weight was measured using a mobile scale that was accurate to 0.01 kg and calibrated before use. Participants were instructed to remain still until the digital display stabilized, at which point their weights were recorded. Height was measured using a mobile stadiometer accurate to 0.1 cm, and participants were asked to stand straight with their knees together during the measurement.

Physical fitness_Lower limb muscle strength

30-Second Chair Stand will used to assess lower limb muscle strength. The required tools will include a straight-backed chair (43 cm seat height) and a timer. Participants will sit in the middle of the chair with their feet shoulder-width apart, crossing their arms at the wrists close to their chest. They will then stand fully and sit back down, counting this as one movement, which will be repeated for 30 seconds after the initial instruction.

Physcal fitness_Upper limb muscle strength

30-second Arm Curl will be used to evaluate upper limb muscle strength. This test will measure upper body strength using a 5-pound dumbbell, a chair without armrests, and a timer. Conducted on the stronger arm, participants will curl their arm through a full range of motion, turning the palm upward. They will fully bend and straighten the arm at the elbow, repeating this as many times as possible within 30 seconds.

Physical fitness_Aerobic endurance

Aerobic endurance will be measured by a 2-Minute Step Test. A timer will be used for this procedure. Participants will stand straight next to a wall, where a mark will indicate the midpoint between the kneecap and hip bone. They will step for two minutes, lifting their knees to the mark's height.

Physical fitness_Lower body flexibility

Lower body flexibility will be assessed by a Chair Sit-and-Reach Test. The required tools will include a ruler and a straight-backed chair about 43 cm high. Participants will sit on the edge of the chair, with one foot flat on the floor and the other leg extended forward, keeping the knee straight and the ankle at a 90° angle. They will reach forward toward their toes with overlapping hands, maintaining a straight back and keeping their heads up. The distance from their fingertips to their toes will be measured and held for a moment.

Physical fitness_Upper body flexibility

Upper body flexibility will be assessed by the Back Scratch Test. The required tool will be a ruler. Participants will place one hand behind their head and over their shoulder, reaching as far as possible with the palm against the body and fingers pointing down. The other arm will be positioned behind the back, with the palm facing outward and fingers pointing up, reaching to overlap the fingertips of both hands. The distance between the tips of the middle fingers will be measured.

Physical fitness_Mobility and dynamic balance

Mobility and dynamic balance will be measured by the 8-Foot Up-and-Go Test. The required tools will include a timer, a straight-backed chair about 43 cm high, a cone marker, and a measuring tape. The cone will be placed 2.4 m in front of the chair. Participants will start by sitting with their hands on their knees and feet flat on the ground. They will then stand up and walk quickly (without running) to round the cone and return to sit down. The time taken from standing to sitting will be measured.

Fear of falling

Fear of falling (FOF) will be measured using the Chinese version of the Falls Efficacy Scale-International (FES-I). This scale includes questions adapted from the original 16-item FES-I questionnaire to evaluate FOF during specific daily activities. The total score of the questionnaire ranges from 16 to 64, and a higher score indicates that the individual perceives themselves as having a significant fear of falling, which can lead to reduced activity levels and an increased risk of social isolation. The Chinese version of SFES-I demonstrated good internal consistency and reliability, with a Cronbach's α of 0.88.

Perceived quality of life

The quality of life will be assessed using the brief version of the Hong Kong Chinese WHO Quality of Life Scale (WHOQOL-BREF) (Cronbach's α = .73 - .84). The scale includes 28 items, covering four dimensions of how older adults perceive their quality of life. The total score of the questionnaire ranges from 28 to 140, and a higher score indicates that the individual feels they have a high quality of life.