BACKGROUND: Shoulder girdle pain is a common disabling complaint with a high lifetime prevalence. Interventions aimed at decreasing shoulder pain without stressing shoulder girdle structures have the potential to improve participation in multimodal shoulder rehabilitation programs. HYPOTHESIS/PURPOSE: The aim of this study was to determine the acute effects of moderate intensity lower extremity exercise on mechanically induced shoulder pain in individuals without shoulder injury. It was hypothesized that participants would exhibit less shoulder pain, as indicated by increased pain thresholds, following lower extremity exercise. STUDY DESIGN: Repeated measures study. METHODS: Thirty (30) healthy participants were recruited to participate in this study. Pain pressure algometry was used to mechanically induce shoulder pain over the infraspinatus muscle belly. This was performed on the dominant shoulder before and immediately after performing 10 minutes of moderate intensity lower extremity exercise using a recumbent exercise machine. Heart rate and rate of perceived exertion were measured following exercise. Repeated measures ANOVA was used to compare pain pressure threshold scores between the baseline and post-exercise time points. Significance was set at p ≤ 0.05 . Effect size (ES) was calculated using Glass's Δ. RESULTS: Moderate intensity lower extremity aerobic exercise led to significantly (F = 8.471, p = 0.003) decreased evoked shoulder pain in healthy adults with moderate effect sizes (0.30-0.43). CONCLUSIONS: Lower extremity aerobic exercise significantly decreased pain of the infraspinatus in this sample of young healthy participants. Utilization of lower extremity exercise may be of benefit for younger patients to decreased acute shoulder pain. LEVEL OF EVIDENCE: 2b: individual cohort study.

This study assessed the effect of an eight-minute cycling intervention using varying intensities on exercise-induced hypoalgesia (EIH). Generally, current research examines EIH using protocols that last for more than 10 minutes and reach 75% of an individual's VO2 peak. The main objective of this study was to examine the effect of varying intensities on pressure pain threshold (PPT) and heat pain threshold (HPT) at the thigh and forearm, tested pre- and post-cycling intervention. Healthy male participants (n=16) performed a graded exercise test on a cycle ergometer to establish their peak power output (PPO). In subsequent visits, participants completed five different 8-minute cycling interventions, with intensities randomly assigned to one of three counterbalanced orders. HPT and PPT were applied to the thigh and forearm two times before and after each cycling intervention. Additionally, there was a notable effect of intensity on PPT in the thigh, with significant changes at intensities of 90% (p = 0.024) and 100% (p = 0.003). In the forearm, repeated measures ANOVA indicated that there was no significant interaction or main effect for intensity and time. Similarly, for HPT, the analysis did not show significant interaction or main effects for both intensity and location. This study was the first to examine EIH using an 8-minute cycling intervention on a cycling ergometer at individualized intensities. Higher intensity cycling sessions generated EIH locally in the thigh using PPT. This intervention appeared to target the nociceptors activated by mechanical, rather than thermal stimuli, further highlighting the multi-faceted nature of EIH. A short but high intensity cycling intervention may have clinical relevance, as it can provide an intervention to reduce localized pain immediately after exercise using a pressure pain stimulus.

Introduktion: En minskad smärtkänslighet som uppkommer under eller efter träning är ett fenomen som kallas för träningsinducerad hypoalgesi (Exercise-induced hypoalgesia, EIH). Metodiken för studier om EIH är mångsidig och resultaten har därför inte alltid varit samstämmiga. Aerob träning har visat sig kunna höja smärttröskeln och minska smärtkänsligheten hos individer. Forskningen om aerob kapacitet och dess samband med EIH hos friska individer är bristfällig.  Syfte: Att undersöka effekten av ett aerobt träningspass på smärtkänslighet samt att analysera sambandet mellan aerob kapacitet och smärtkänslighet hos friska individer.  Metod: Ett submaximalt cykeltest utfördes av 19 friska individer mellan 20-38 år, i syfte att estimera maximal syreupptagningsförmåga (VO2max). Detta var följt av ett EIH-test för att undersöka eventuell höjning av trycksmärttröskeln (Pressure pain threshold, PPT). EIH-testet bestod av ett 15 minuters cykelpass på 75% av VO2max där mätning av PPT utfördes på arbetande (ben) respektive vilande (arm) muskulatur, direkt före och direkt efter träningspasset.   Resultat: En signifikant ökning av PPT för arbetande muskulatur (p=0,018) påvisades efter träning. Ingen signifikant förändring av PPT påvisades för vilande muskulatur (p=0,052). Det observerades inget signifikant samband mellan maximal syreupptagningsförmåga (VO2max) och EIH-effekt (ben, p= 0,860; arm, p= 0,942).  Konklusion: Ett högintensivt aerobt cykelpass gav en signifikant höjning av PPT för den arbetande muskulaturen. Inget signifikant samband påvisades mellan VO2max och EIH-effekt (differensen mellan PPT direkt efter och direkt före träning). Ytterligare studier med ett högre deltagarantal behövs för att undersöka detta samband mer ingående samt för att underlätta jämförelser mellan studier.