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

Official title

Pain in Athletes INtervention (PAIN): A Randomized Crossover Clinical Trial in Aging Former Athletes, Master's Athletes, and Nonathletes

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).

Detailed description

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

• Other Moderate-Intensity Strength Exercise Intervention
  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
• Other Moderate-Intensity Aerobic Exercise Intervention
  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. Quantita

Primary outcome measures

• Pain Tolerance [Time frame: Baseline (Aim 1a)]
• Pressure Pain Threshold (PPT) [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 [Time frame: Remote monitoring for 2 weeks during the study (Aim 1b)]
• Sedentary Behavior [Time frame: Remote monitoring for 2 weeks during the study (Aim 1b)]

Secondary outcome measures (7)

• Pain Intensity (pain perception) [Time frame: Baseline]
• Michigan Body Map for Pain (pain perception) [Time frame: Baseline]
• Temporal Summation of Pain (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) [Time frame: Baseline]
• Numeric Pain Rating Scale [Time frame: 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)]
• Prolonged Bouts of Sedentary Behavior [Time frame: Remote monitoring for 2 weeks during the study (Aim 1b)]
• Sleep Duration [Time frame: Remote monitoring throughout the study (i.e., about 2-3 weeks)]

Eligibility criteria

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:

• 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)
• 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)
• 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

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Crossover

Masking

Single blind

Primary purpose

Treatment

Study locations

United States · 1 center

• Marquette University — Milwaukee

Publications

• Drawer S, Fuller CW. Propensity for osteoarthritis and lower limb joint pain in retired professional soccer players. Br J Sports Med. 2001 Dec;35(6):402-8. doi: 10.1136/bjsm.35.6.402. PMID 11726474
• Wewege MA, Jones MD. Exercise-Induced Hypoalgesia in Healthy Individuals and People With Chronic Musculoskeletal Pain: A Systematic Review and Meta-Analysis. J Pain. 2021 Jan;22(1):21-31. doi: 10.1016/j.jpain.2020.04.003. Epub 2020 Jun 26. PMID 32599154
• Geisler M, Herbsleb M, de la Cruz F, von Au S, Schumann A, Croy I, Bar KJ. Profound neuronal differences during exercise-induced hypoalgesia between athletes and non-athletes revealed by functional near-infrared spectroscopy. J Physiol. 2026 Apr;604(7):2738-2756. doi: 10.1113/JP289766. Epub 2026 Feb 26. PMID 41749046
• Purcell C, Duignan C, Fullen BM, Ryan S, Ward T, Caulfield B. Comprehensive assessment and classification of upper and lower limb pain in athletes: a scoping review. Br J Sports Med. 2023 May;57(9):535-542. doi: 10.1136/bjsports-2022-106380. Epub 2023 Feb 9. PMID 36759138
• Simon JE, Docherty CL. The Impact of Previous Athletic Experience on Current Physical Fitness in Former Collegiate Athletes and Noncollegiate Athletes. Sports Health. 2017 Sep/Oct;9(5):462-468. doi: 10.1177/1941738117705311. Epub 2017 May 5. PMID 28475420
• Schwenk TL, Gorenflo DW, Dopp RR, Hipple E. Depression and pain in retired professional football players. Med Sci Sports Exerc. 2007 Apr;39(4):599-605. doi: 10.1249/mss.0b013e31802fa679. PMID 17414796
• Simon JE, Lorence M, Docherty CL. Health-Related Quality of Life in Former National Collegiate Athletic Association Division I Collegiate Athletes Compared With Noncollegiate Athletes: A 5-Year Follow-Up. J Athl Train. 2021 Mar 1;56(3):331-338. doi: 10.4085/107-20. Epub 2021 Feb 18. PMID 33150419
• Dzau VJ, Pizzo PA. Relieving pain in America: insights from an Institute of Medicine committee. JAMA. 2014 Oct 15;312(15):1507-8. doi: 10.1001/jama.2014.12986. No abstract available. PMID 25321905

Identifiers

NCT: NCT07502742 · IRB#5050

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗