The Impact of Rapid Heat Stress on Firefighters' Strength, Dynamic Balance, and Movement Quality
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 26
- 试验地点
- 1
- 主要终点
- Forward-Step-Down Test
研究概览
简要总结
This study will examine the effect of heat stress on factors that influence musculoskeletal injury risk in firefighters. Participants will attend 4 data collection sessions. 1: informed consent, screening, and familiarization. 2: pre-tests (strength, balance, and movement quality). 3: heat stress (rapid or gradual) followed by post-tests (strength, balance, and movement quality). 4: heat stress (rapid or gradual) followed by post-tests.
详细描述
This study utilizes a crossover design, with participants acting as their own controls and participating in both the control (gradual uncompensable heat) and experimental (rapid heat stress (RHS)) conditions. The independent variable is the type of heat stress (uncompensable or rapid). The dependent variables are: peak concentric muscle torque (hip abductors, hip adductors, knee flexors, knee extensors), dynamic balance (Y-Balance Test, Firefighter-Specific Functional-Balance Test (FFSFBT)), and frontal plane movement quality (Forward-Step-Down Test (FSDT)). These will be measured three times, once during pre-testing and twice during post-testing as described below.
The study will consist of four visits. Visit one will be the informed consent and familiarization to the outcome measures. Participants will be educated on filling out the 24-hour food/drink diary, and asked to standardize their diet as close as possible to this record the 24 hours before visits 2, 3, and 4. Injury history and demographic data will be collected at visit 1.
Visit two will be the pre-test data collection, which will occur at approximately 22°C. Participants will complete all outcome measures (torque, balance, movement quality measures). Body composition will also be measured in the BodPod at this time.
Before visits 2, 3, and 4, participants will follow the safety guidelines outlined below to ensure proper hydration:
- 48 hours before: no heat stress (will contact participant to determine if they have been called out to a live fire. Data collection will be postponed if so)
- 24 hours before: no alcohol consumption, no energy drink consumption (normal coffee/tea is allowed)
- 24 hours before: no physical activity (exercise or vigorous play)
- 24 hours before: drink 3.7L of total water to make sure to be well-hydrated
- 2 hours before: eat last meal
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Prevention
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 57 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •professional firefighter
- •healthy per the Physical Activity Readiness Questionnaire+ screening
排除标准
- •unable to swallow core temperature capsule
- •unable to follow pre-testing hydration criteria
- •musculoskeletal injury in the past 3 months that limits ability to perform outcome measures
- •females with known pregnancy (risk of hyperthermia to fetus)
结局指标
主要结局
Forward-Step-Down Test
时间窗: Familiarization trials (session 1, recruitment); pre-testing (baseline, session 2 (approximately day 7)); post-control and post-experimental sessions (session 3 (approximately day 14) & 4 (approximately day 21)).
a step-down task that is performed off a 20 cm box. Five repetitions are performed to give one score (minimum score 0, maximum score 6). A higher score is worse.
Y-Balance Test
时间窗: Familiarization trials (session 1, recruitment); pre-testing (baseline, session 2 (approximately day 7)); post-control and post-experimental sessions (session 3 (approximately day 14) & 4 (approximately day 21)).
A dynamic balance test that is performed on the dominant leg, reaching in the anterior, posteromedial, and posterolateral directions. The length of reach is standardized to participants' leg length. A higher score is better, with 0 being the minimum distance and the maximum distance in anterior reach being 126cm, and the maximum posteromedial and posterolateral directions being 149cm.
Firefighter Specific Functional Balance Test
时间窗: Familiarization trials (session 1, recruitment); pre-testing (baseline, session 2 (approximately day 7)); post-control and post-experimental sessions (session 3 (approximately day 14) & 4 (approximately day 21)).
A dynamic balance test performed by stepping down from a 15cm box, walking across a low beam (4cm high), and stepping up onto a 10cm box, turning around, and returning to the original box. 8 Trials are performed. In 4 trials, a bar is placed at 75% of the participant's height for them to negotiate while on the beam. A faster time with fewer errors is better.
Knee Flexor/Extensor Isokinetic Test
时间窗: Familiarization trials (session 1, recruitment); pre-testing (baseline, session 2 (approximately day 7)); post-control and post-experimental sessions (session 3 (approximately day 14) & 4 (approximately day 21)).
Knee flexor/extensor isokinetic strength will be tested at 60°, 180°, and 300° per second from the seated position with 5, 10, and 10 concentric contractions for each speed. A higher reading of strength is better.
Hip Abductor/Adductor Isokinetic Test
时间窗: Familiarization trials (session 1, recruitment); pre-testing (baseline, session 2 (approximately day 7)); post-control and post-experimental sessions (session 3 (approximately day 14) & 4 (approximately day 21)).
Hip abductor/adductor strength will be tested at 30°, 60°, and 120° per second from the standing position. A higher reading of strength is better.
次要结局
- Injury Occurrence(6 months, 12 months, 18 months, 24 months after session 4.)