The Effect of Mechanical Loading and Bone Loss on the Relationship Between Motor Neuron Pool Activity and H-Reflex Amplitude
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 发起方
- 入组人数
- 24
- 试验地点
- 1
- 主要终点
- H-reflex Amplitude
研究概览
简要总结
Weight-bearing exercises (e.g., running, jumping, whole-body vibration) are widely practiced due to their beneficial effects on bone development and their role in the prevention and treatment of osteoporosis. However, the underlying neuroregulatory mechanisms responsible for these positive effects have not yet been fully understood. Two main neuromodulatory mechanisms have been proposed in the literature: (i) spinal reflexes originating from muscle spindles (stretch reflex, tonic vibration reflex), and (ii) the bone myoregulation reflex (BMR) based on load-sensitive osteocytes.
It is well established that increased voluntary contraction and the associated rise in background EMG activity, that is, motor neuron pool activity, enhance muscle spindle-based reflex responses (such as the H-reflex and tendon reflex). In contrast, it has been demonstrated that the H-reflex is suppressed during bone-loading activities such as single-leg stance, jumping, or whole-body vibration.
This study is based on two hypotheses:
- As mechanical loading increases, Ia inhibitory effects intensify, leading to greater H-reflex suppression.
- During whole-body vibration, the H-reflex is suppressed due to Ia inhibition.
If this inhibition originates from load-sensitive receptors-osteocytes-and thus from the BMR, then in osteoporosis, where osteocyte number and function are reduced, H-reflex suppression will be diminished.
The aim of this research is to test these hypotheses. Confirmation of these assumptions would suggest that reflex control during weight-bearing exercise occurs predominantly through osteocyte-mediated BMR mechanisms rather than muscle spindle-based mechanisms such as the stretch or tonic vibration reflex.
详细描述
EMG and Force Data Acquisition
Surface EMG signals from the soleus muscle, accelerometer data from the whole-body vibration platform, and force sensor data will be collected at a 2 kHz sampling rate using a data acquisition system (CED 3601 Power 1401 MKII digital-to-analogue converter and CED 1902 Quad System MKIII amplifier). Data analysis will be performed using Spike2 version 7.20 software.
Subjects will be tested while standing on both feet. A force load cell (FC2231-0000-0100-L Compression Load Sensor, France) will be placed under the right heel of the subjects to obtain real-time readings of the weight applied to the right heel.
Before attaching the electrodes, any hair on the skin will be shaved, and the skin will be cleaned with alcohol wipes to remove surface oils. An ECG gel will be applied to increase skin conductivity.
A PowerPlate Pro5 (London, UK) device will be used to apply whole-body vibration.
研究设计
- 研究类型
- Interventional
- 分配方式
- Non Randomized
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- Single (Outcomes Assessor)
盲法说明
Outcome assessor and statistician will be blinded to the groups of participants.
入排标准
- 年龄范围
- 18 Years 至 65 Years（Adult, Older Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •Being in the postmenopausal period
- •For the osteoporosis group: having femoral osteoporosis (femoral neck or total femur T-score ≤ -2.5)
- •For the control group: having no osteoporosis or osteopenia (femoral neck and total femur T-scores > -1, and L1-L4 and L2-L4 T-scores > -1)
- •Being a volunteer
排除标准
- •Receiving osteoporosis treatment
- •Having a peripheral or central nervous system disorder (e.g., stroke, polyneuropathy, radiculopathy, entrapment neuropathy, etc.)
- •Having acquired or hereditary muscle diseases (myopathies)
- •Having active painful lower extremity pathologies (e.g., osteoarthritis, inflammatory joint diseases, etc.)
- •Having cardiac arrhythmias
- •Having a history of other metabolic bone diseases
- •Having skin lesions at the electrode placement sites on the lower extremities
- •Being older than 65 years
结局指标
主要结局
H-reflex Amplitude
时间窗: During the day of testing
H reflex will be measured 10 times each in 5 different mechanical loads and during 1 minute whole-body vibration. Average amplitude of 10 measurements will be calculated.
次要结局
- Bone myoregulation reflex latency(During the day of testing)
研究者
Fuat Orhun Alayoglu
Attending physician
Istanbul Physical Medicine Rehabilitation Training and Research Hospital