This study investigates how acute exercise-induced muscular pain affects sleep quality and sleep architecture in people with insomnia compared to healthy sleepers. Sleep disturbances and pain often influence each other, creating a negative cycle; however, it remains unclear how acute muscle pain-such as delayed-onset muscle soreness (DOMS) after strenuous exercise-alters continuous sleep parameters and pain sensitivity differently in clinical insomnia populations versus healthy controls. Participants will be divided into two groups: individuals with clinical insomnia and age- and sex-matched healthy sleepers. Both groups will undergo a standardised exercise protocol designed to safely induce temporary, acute muscular soreness (DOMS). Objective sleep parameters (measured via wrist actigraphy) and subjective sleep parameters (measured via sleep diaries), will be monitored before and after the pain induction. The primary goal is to determine whether individuals with insomnia experience greater sleep disruption and altered pain recovery trajectories following an acute painful event compared to healthy individuals.
Study Type
OBSERVATIONAL
Enrollment
80
Eccentric hamstring exercise
the Hong Kong Polytechnic University
Hong Kong, Hong Kong
RECRUITINGSleep diary: Total Sleep Time
Assessed using a daily consensus sleep diary. Total Sleep Time is calculated as the total time spent asleep, derived from the total time in bed (bedtime to wake time) minus sleep onset latency and wake after sleep onset. Higher values indicate longer sleep duration.
Time frame: Day 0 to Day 14
Sleep diary: Sleep Onset Latency (SOL)
Assessed using a daily consensus sleep diary. Sleep Onset Latency is the estimated time (in minutes) it takes to fall asleep after turning off the lights. Lower values indicate better sleep onset.
Time frame: Day 0 to Day 14
Sleep diary: Wake After Sleep Onset (WASO)
Assessed using a daily consensus sleep diary. WASO is calculated as the total duration of wakefulness (in minutes) between initial sleep onset and final awakening, derived from the number of night awakenings multiplied by their average duration. Lower values indicate better sleep continuity.
Time frame: Day 0 to Day 14
Sleep diary: Sleep Efficiency (SE)
Assessed using a daily consensus sleep diary. Sleep Efficiency is calculated as the percentage of time in bed spent asleep: \[(Total Sleep Time / Total Time in Bed) × 100\]. Total Sleep Time is derived from total time in bed (time between bedtime and rise time) minus sleep onset latency and nocturnal wakefulness (calculated from the number and duration of night awakenings). Scores range from 0% to 100%, with higher percentages indicating better sleep quality.
Time frame: Day 0 to Day 14
Actigraphy: Total Sleep Time (TST)
Measured objectively using a wrist-worn ActiGraph accelerometer and validated sleep-scoring algorithms. Total Sleep Time is defined as the total amount of time spent sleeping between bedtime and rise time. Higher values indicate longer sleep duration.
Time frame: Day 0 to Day 14
Actigraphy: Sleep Onset Latency (SOL)
Measured objectively using a wrist-worn ActiGraph accelerometer. Sleep Onset Latency is the time (in minutes) between the initial bedtime (lights out) and the onset of continuous sleep detected by the algorithm. Lower values indicate faster sleep onset and better sleep initiation.
Time frame: Day 0 to Day 14
Actigraphy: Wake After Sleep Onset (WASO)
Measured objectively using a wrist-worn ActiGraph accelerometer. WASO is defined as the total number of minutes spent awake after initial sleep onset and before final awakening, as determined by epoch-by-epoch movement counts. Lower values indicate better sleep continuity and fewer night awakenings.
Time frame: Day 0 to Day 14
Actigraphy: Sleep Efficiency (SE)
Measured objectively using a wrist-worn ActiGraph accelerometer. Sleep Efficiency is calculated as the percentage of time in bed spent asleep: \[(Total Sleep Time / Total Time in Bed) × 100\]. Values range from 0% to 100%, with higher percentages indicating better sleep quality and efficiency.
Time frame: Day 0 to Day 14
Muscle damage severity: Muscle pain
Muscle pain will be measured by an 11-point NRS, with 0 represents "no pain" and 10 indicating "worst imaginable pain". The Outcome will be recorded at rest, reach for the floor with knees straight, and during a validated hamstring provocative manoeuvre, the "taking-off shoe" test.
Time frame: Day 0 to Day 14
Muscle damage severity: Muscle soreness
Muscle soreness will be measured by an 7-point Likert scale, with 0= A complete absence of soreness," 1 = "A light soreness in the muscle felt only when touched/a vague ache," 2 = "A moderate soreness felt only when touched/a slight persistent pain," 3 = "A light muscle soreness when walking up and down stairs," 4 = "A light muscle soreness when walking on flat surface," 5 = "A moderate muscle soreness, stiffness, or weakness when walking," 6 = "A severe muscle soreness, stiffness, or weakness that limits my ability to move."
Time frame: Day 0 to Day 14
Sleep Questionnaires: the Insomnia Severity Index (ISI)
The ISI is a 7-item self-report questionnaire assessing the nature, severity, and impact of insomnia. Each item is rated on a 5-point Likert scale (0 to 4). The total score ranges from 0 to 28, with higher scores indicating greater severity of insomnia
Time frame: Day 0 and Day 7
Sleep Questionnaires: The Pittsburgh Sleep Quality Index (PSQI)
The PSQI is a 19-item self-report questionnaire that evaluates sleep quality and disturbances over a 1-month time interval. It generates seven component scores: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleep medication, and daytime dysfunction. Each component is scored from 0 to 3. The sum of these seven component scores yields a global PSQI score ranging from 0 to 21, where higher scores indicate poorer sleep quality.
Time frame: Day 0 and Day 7
Psychological measurement: Depression, Anxiety, and Stress Scale (DASS-21)
Assessed using the 21-item Depression Anxiety Stress Scales (DASS-21). The instrument consists of three 7-item subscales measuring depression, anxiety, and stress. Each item is rated on a 4-point Likert scale ranging from 0 ("did not apply to me at all") to 3 ("applied to me very much or most of the time"). Sum scores for each subscale are calculated and multiplied by 2 to yield total scores ranging from 0 to 42 for each dimension (Depression: 0-42, Anxiety: 0-42, Stress: 0-42), with a total overall score ranging from 0 to 126. Higher scores indicate greater levels of psychological distress/severity.
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Time frame: Day 0, Day 7, and Day 9
Psychological measurement: Pain Catastrophizing Scale (PCS)
Assessed using the 13-item Pain Catastrophizing Scale (PCS) to evaluate catastrophic thoughts and feelings associated with pain (comprising rumination, magnification, and helplessness subscales). Each item is rated on a 5-point Likert scale from 0 ("not at all") to 4 ("all the time"). The total score ranges from 0 to 52, with higher scores indicating higher levels of pain catastrophizing.
Time frame: Day 0, Day 7, and Day 9
Psychological measurement: Fear of Pain Questionnaire (FPQ-9)
Assessed using the 9-item short form of the Fear of Pain Questionnaire (FPQ-9) to assess fear of different painful experiences across severe pain, minor pain, and medical pain domains. Each item is rated on a 5-point Likert scale from 1 ("not at all") to 5 ("extreme"). The total score ranges from 9 to 45, with higher scores indicating greater fear of pain.
Time frame: Day 0, Day 7, and Day 9
Psychological measurement: Tampa Scale for Kinesiophobia (TSK-11)
Assessed using the 11-item Tampa Scale for Kinesiophobia (TSK-11) to evaluate fear of movement or (re)injury. Each item is scored on a 4-point Likert scale ranging from 1 ("strongly disagree") to 4 ("strongly agree"). The total score ranges from 11 to 44, with higher scores indicating greater fear of movement/kinesiophobia.
Time frame: Day 0, Day 7, and Day 9
Physical Activity Level: International Physical Activity Questionnaire - Short Form (IPAQ-SF)
Assessed using the 7-item International Physical Activity Questionnaire - Short Form (IPAQ-SF). The questionnaire measures the duration (minutes) and frequency (days) of walking, moderate-intensity activities, and vigorous-intensity activities performed over the last 7 days. Total physical activity volume is calculated as MET-minutes per week (MET-min/week) using standardised MET energy expenditure values: Walking = 3.3 METs, Moderate PA = 4.0 METs, and Vigorous PA = 8.0 METs. Total score is the sum of (METs × minutes × days) across all three domains, starting at 0 with no strict upper limit. Higher scores indicate higher levels of overall physical activity.
Time frame: Day 0 and Day 7