Pain in Aging Former Athletes, Master's Athletes, and Nonathletes

Marquette University90 enrolled

Overview

The goal of this clinical trial is to determine how male and female former athletes experience pain and respond to moderate-intensity exercise (strength versus aerobic) compared with both current master's athletes and nonathletes. The main questions this study aims to address are: 1. How do former athletes, master's athletes, and nonathletes experience pain? 2. How do different types of moderate-intensity exercise (strength versus aerobic exercise) influence pain in former athletes, master's athletes, and nonathletes? Participants will complete 3 different testing sessions: 1. Baseline testing including assessments of strength, cardiorespiratory fitness, and pain; 2. Strength exercise: pain assessments will occur before and after moderate-intensity strength training exercise; 3. Aerobic exercise: pain assessments will occur before and after moderate-intensity aerobic exercise. There will be a washout period of approximately one week or greater between each of the three different testing sessions. The order of conditions (strength versus aerobic exercise) will be randomized (crossover randomized trial design).

Two major health challenges facing midlife adults in our society are chronic pain and insufficient physical activity (PA). Chronic pain is highly prevalent among females and those who previously engaged in substantial vigorous PA, such as former competitive athletes. Exercise (i.e., a specific planned subtype of PA) is one of the best interventions for optimizing health, maintaining function, and preserving cardiorespiratory fitness - yet ironically often not continued among midlife adults who were highly physically active as youth and young adults in competitive sports. While PA and other lifestyle behaviors (e.g., sleep) likely influence pain processing and response to exercise, the mechanisms underlying pain in males and females with distinct PA trajectories are unknown. Pain is a common and critical barrier to regular exercise. Yet exercise has paradoxical effects on pain, generally increasing pain during exercise and providing pain relief after, i.e., exercise-induced hypoalgesia. While higher exercise intensities may lead to greater exercise-induced hypoalgesia, the greater pain and discomfort experienced during high-intensity exercise may prevent uptake, making moderate-intensity exercise a promising solution balancing physiological benefits and exercise-induced hypoalgesia. The investigators' long-term objective is to alleviate pain, increase PA, and improve health in midlife and aging adults. This randomized crossover clinical trial will determine how markedly different PA trajectories and sex influence pain, lifestyle behaviors, and the pain response to exercise (exercise-induced hypoalgesia). Given that pain is affected by PA and sports history, this proposal will examine pain processing in midlife males and females with distinct PA trajectories evenly split across 3 unique groups: 1) former athletes no longer participating in sports; 2) master's athletes; and 3) nonathletes. In order to compare pain perceptions and processing in former athletes, master's athletes, and nonathletes, quantitative sensory testing and validated questionnaires will be used. Lifestyle behaviors (PA and sleep) will be assessed using wearable devices. Moderate-intensity strength and aerobic exercise interventions will be included to determine how these influence the pain perceptions of former athletes, current master's athletes and nonathletes. Full participation will involve completing three in-person sessions including baseline assessment session and two intervention sessions (i.e., follow-up 1 and follow-up 2 at approximately 1 week intervals) at Marquette University as well as wearing a small physical activity monitor for 2 weeks following baseline session and an OURA ring for the duration of the study. Aim 1: Determine the impact of physical activity history (group) and sex on (1a) pain processing and (1b) lifestyle behaviors in midlife adults (former athletes, master's athletes, and nonathletes). Aim 2: Quantify the effect of physical activity history (group) and sex on the change in pain response to moderate-intensity exercise and explore differences in pain response to exercise modality (i.e., strength versus aerobic).

Interventions

Moderate-Intensity Strength Exercise InterventionOTHER

Participants will perform 10 isometric knee extension repetitions unilaterally on both sides separately for 10 seconds with each repetition at 50% of their maximal volitional contraction (MVC) on an electromechanical dynamometer. Participants will be provided 50 seconds rest in between repetitions. Numeric pain intensity ratings (0-10) and rating of perceived exertion (RPE) will be recorded before, during, and following exercise. Quantitative Sensory Testing (i.e., PPTs and TSP) will be assessed before and after the exercise intervention. If there is a more affected limb with regards to pain, the less affected limb will be exercised first. If there is not a more affected limb, side will be randomized. A warm up will be performed prior to the intervention.

Moderate-Intensity Aerobic Exercise InterventionOTHER

Participants will complete aerobic exercise at 40-59% of their heart rate reserve (HRR) through the mode of incline walking on a treadmill for 30 minutes with a 2 -minute warm up and 2-minute cool down with a target intensity of \~50% HRR. Adjustments will be made to the incline and speed throughout the intervention as needed to maintain 40-59% HRR range. Numeric pain intensity ratings (0-10) and rating of perceived exertion (RPE) will be recorded before, during, and following exercise. Quantitative Sensory Testing (i.e., PPTs and TSP) will be assessed before and after the exercise intervention. Heart rate will be measured throughout the walking intervention to ensure the participant is within the targeted range for moderate intensity; pre- and post-aerobic intervention heart rate and blood pressure will be taken.

Eligibility

Sex: ALLMin age: 35 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria (General): * Age: 35 years through 65 years * Current master's athlete, former competitive athletes, or non-athlete control (see details below) * Ability to participate in exercise and exercise testing based on the Physical Activity Readiness Questionnaire (PAR-Q+) Exclusion Criteria (General): * Currently pregnant or planning to become pregnant during the study * Currently taking heart rate lowering medications (e.g., betablockers) that would impact exercise testing * Contraindications to ice such as Raynaud's, cryoglobulinemia, cold urticaria, and/or impaired circulation or sensation * Fibromyalgia and/or chronic regional pain syndrome (CRPS) * Myocardial infarction or pulmonary embolism in the last 12 months, active cancer, a pacemaker, or any additional condition or disease that would preclude the individual from being able to perform the tests safely Participants will be enrolled into one of the following three mutually exclusive groups according to the following criteria: 1. Former Competitive Athlete: Prior participation in competitive sports at the Tier 3 level or above as per McKay et al. (2022): i.e., "national-level representatives who are performing structured and/or periodized training and are developing proficiency in skills required to perform their sport at the highest level; this tier includes individuals participating in Provincial/State or Academy Programs" or higher participation in sport; Not currently participating in any recreational or competitive sports over the last 5 years (Tier 2 or above) 2. Master's Athlete: Currently (within the past year) participating in sports at the Tier 2 level or above (i.e., committed to sports-specific training at least 3 times per week with the intent to compete)(McKay et al., 2022) 3. Nonathlete Control: No prior participation in sport at the Tier 3 (Highly Trained/National) Level or above and not currently participating in any competitive sports (i.e., Tier 2 or above) (McKay et al., 2022) for at least 5 years

Outcomes

Primary Outcomes

Pain Tolerance

The maximum stimulus intensity that the participant can tolerate will be measured by placing a thermode (Q-Sense, Medoc) on the ventral forearm. Three trials will be completed with the baseline temperature set at 35°C that increases at a rate of 1°/s with a maximum temperature of 50°C. Participants will be asked to press a timing device when they can no longer tolerate the temperature (i.e., pain tolerance), and this temperature will be recorded as the maximum stimulus intensity.

Time frame: Baseline (Aim 1a)

Pressure Pain Threshold (PPT)

Pressure Pain Thresholds (PPTs) will be used to measure group differences in pain sensitivity at baseline and the hypoalgesic response (increase in PPTs) during the exercise sessions with a pressure algometer (Algomed, Medoc) at the exercising limb, contralateral limb, and systemically at the right upper trapezius muscle. Two trials separated by a 10-second interval will be performed at each site with a 1cm\^2 rubber tip at a rate of 50 kPA/sec. Participants will be instructed to press a timing device when the pressure first changes to pain (i.e., pain threshold). Practice trials with be performed on the fourth digit fingernail bed prior to formal assessment at quad/trap and order will be randomized. The change scores from pre- to post-strength exercise and from pre- to post-aerobic exercise will be used as the primary outcome in Aim 2.

Time frame: Baseline, Pre-/Post-Exercise at Follow-up Session 1 (approximately 1 week after baseline), and Pre-/Post-Exercise at Follow-up Session 2 (approximately 2 weeks after baseline) (Aim 2)

Physical Activity - Step Counts

Physical activity (PA) will be monitored continuously using an activPAL activity monitor. Step counts will be recorded as the average number of steps taken per day.

Time frame: Remote monitoring for 2 weeks during the study (Aim 1b)

Sedentary Behavior

Total sedentary behavior will be assessed using an activPAL activity monitor and recorded as the average daily amount of time in wakeful sedentary behavior (hours:minutes).

Time frame: Remote monitoring for 2 weeks during the study (Aim 1b)

Secondary Outcomes

Pain Intensity (pain perception)

The Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity-SF v.1.0 3a will be collected at baseline to capture average pain and worst pain intensity over the past 7 days and right now. The survey has 3 questions where respondents rates pain from no pain (1) to very severe pain (5). The total raw score ranges from 3 to 15 with higher scores indicating more severe pain.

Time frame: Baseline

Michigan Body Map for Pain (pain perception)

Pain distribution or location at rest and with movement will be assessed using the Michigan Body Map for Pain (validated questionnaire).

Time frame: Baseline

Temporal Summation of Pain (TSP)

Temporal summation of pain (TSP) is an increase in pain with a repetitive or constant-intensity, noxious stimulus and represents central pain facilitation. A custom-made pressure pain device, used frequently in the assessment of exercise-induced hypoalgesia, will assess TSP and consists of an 8 x 1.5-mm Lucite edge (Romus Inc., Milwaukee, WI) placed on the mid portion of the middle phalanx of the right index finger for 2 min. A 10-N force (equivalent to a 1-kg mass) will be applied to the Lucite edge, and participants will be asked to press a timing device when the pressure first changes to pain (i.e., pain threshold) and to rate the intensity of pain on a 0-10 numerical pain rating scale every 20-s throughout the test. The increase in the pain intensity during the 2-minute test represents TSP.

Time frame: Baseline, Pre-/Post-Exercise at Follow-up Session 1 (approximately 1 week after baseline), and Pre-/Post-Exercise at Follow-up Session 2 (approximately 2 weeks after baseline)

Condition Pain Modulation (CPM)

Condition pain modulation (CPM) is the concept that pain inhibits pain and will be used to indirectly measure the efficiency of descending inhibitory pathways. For the CPM protocol, PPTs (test stimulus) will be measured using a pressure algometer (AlgoMed, Medoc) as described above at the quadriceps and upper trapezius muscles with and without the participant's foot submerged in an ice water bath (conditioning stimulus). An increase in PPTs during the conditioning stimulus represents the pain inhibits pain phenomenon, whereas no change or decrease in PPTs indicates low CPM efficiency.