Histamine-Receptor Antagonists Slow 10-km Cycling Performance in Competitive Cyclists

Patellofemoral Pain Syndrome Is Associated With Chronic Disease and Allergies in 60 997 Distance Runner Race Entrants: SAFER XXX Study

OBJECTIVE

Patellofemoral pain syndrome (PFPS) is a common running-related injury. Independent risk factors associated with PFPS have not been described in a large cohort of distance runners.

DESIGN

Descriptive, cross-sectional study.

SETTING

21.1 and 56 km Two Oceans Marathon races (2012-2015).

PARTICIPANTS

60 997 race entrants.

ASSESSMENT OF RISK FACTORS

Participants completed a compulsory prerace medical screening questionnaire (history of PFPS in the past 12 months, n = 362; no injury history, n = 60 635). Selected risk factors associated with a history of PFPS were explored using univariate & multivariate analyses: demographics, training/running variables, history of chronic diseases (composite chronic disease score), and any allergy.

MAIN OUTCOME MEASURES

Prevalence ratios (PRs, 95% confidence intervals).

RESULTS

Risk factors associated with PFPS (univariate analysis) were increased years of recreational running (PR = 1.09; P = 0.0107), older age (>50 years), and chronic diseases (PR > 2): gastrointestinal disease (PR = 5.06; P < 0.0001), cardiovascular disease (CVD) (PR = 3.28; P < 0.0001), nervous system/psychiatric disease (PR = 3.04; P < 0.0001), cancer (PR = 2.83; P = 0.0005), risk factors for CVD (PR = 2.42; P < 0.0001), symptoms of CVD (PR = 2.38; P = 0.0397), and respiratory disease (PR = 2.00; P < 0.0001). Independent risk factors (multivariate analysis) associated with PFPS (adjusted for age, sex, and race distance) were a higher chronic disease composite score (PR = 2.68 increased risk for every 2 additional chronic diseases; P < 0.0001) and a history of allergies (PR = 2.33; P < 0.0001).

CONCLUSIONS

Novel independent risk factors associated with PFPS in distance runners are a history of multiple chronic diseases and a history of allergies. Identification of chronic diseases and allergies should be considered as part of the clinical assessment of a runner presenting with a history of PFPS.

Factors associated with patellofemoral pain in recreational road cyclists: A cross-sectional study in 59953 cyclists - SAFER XXXIII

OBJECTIVE

Patellofemoral pain (PFP) is a common cycling-related injury, and independent factors need to be identified to enable effective injury prevention strategies. We aim to determine factors associated with PFP in cyclists entering mass community-based events.

DESIGN

Cross-sectional study.

SETTING

2016-2020 Cape Town Cycle Tour.

PARTICIPANTS

Consenting race entrants.

MAIN OUTCOME MEASURES

62758 consenting race entrants completed a pre-race medical questionnaire, and 323 reported PFP. Selected factors associated with PFP (demographics, cycling experience and training, chronic disease history) were explored using multivariate analyses.

RESULTS

Prevalence ratio (PR) of PFP was similar for sex and age groups. Independent factors associated with PFP (adjusted for sex and age) were history of chronic disease [Composite Chronic Disease Score (0-10)(PR = 2.0, p < 0.0001) and any allergies (PR = 2.0, p < 0.0001)].

CONCLUSION

A history of chronic diseases and allergies is associated with PFP in cyclists. Practical clinical recommendations are: 1) that prevention programs for PFP be considered when cycling is prescribed as a physical activity intervention for patients with chronic disease, and 2) that older cyclists presenting with PFP be assessed for the presence of risk factors or existing chronic disease.

International Olympic Committee (IOC) consensus statement on acute respiratory illness in athletes part 2: non-infective acute respiratory illness

Acute respiratory illness (ARill) is common and threatens the health of athletes. ARill in athletes forms a significant component of the work of Sport and Exercise Medicine (SEM) clinicians. The aim of this consensus is to provide the SEM clinician with an overview and practical clinical approach to non-infective ARill in athletes. The International Olympic Committee (IOC) Medical and Scientific Committee appointed an international consensus group to review ARill in athletes. Key areas of ARill in athletes were originally identified and six subgroups of the IOC Consensus group established to review the following aspects: (1) epidemiology/risk factors for ARill, (2) infective ARill, (3) non-infective ARill, (4) acute asthma/exercise-induced bronchoconstriction and related conditions, (5) effects of ARill on exercise/sports performance, medical complications/return-to-sport (RTS) and (6) acute nasal/laryngeal obstruction presenting as ARill. Following several reviews conducted by subgroups, the sections of the consensus documents were allocated to 'core' members for drafting and internal review. An advanced draft of the consensus document was discussed during a meeting of the main consensus core group, and final edits were completed prior to submission of the manuscript. This document (part 2) of this consensus focuses on respiratory conditions causing non-infective ARill in athletes. These include non-inflammatory obstructive nasal, laryngeal, tracheal or bronchial conditions or non-infective inflammatory conditions of the respiratory epithelium that affect the upper and/or lower airways, frequently as a continuum. The following aspects of more common as well as lesser-known non-infective ARill in athletes are reviewed: epidemiology, risk factors, pathology/pathophysiology, clinical presentation and diagnosis, management, prevention, medical considerations and risks of illness during exercise, effects of illness on exercise/sports performance and RTS guidelines.

Validity and Reliability of the Computrainer Lab™ During Simulated 40 and 100 km Time-Trials

The validity and reliability of the Computrainer Lab^™ (CT) was assessed, for the first time, using a high-precision motor-driven calibration rig during simulated variable intensity 40 and 100 km time-trials (TTs). The load patterns imposed by the CT were designed from previously published studies in trained cyclists and included multiple 1 or 4 km bursts in power output. For the 40 and 100 km TTs, cluster-based analyses revealed a mean measurement error from the true workload of respectively 0.7 and 0.9%. However, measurement errors were dependent upon the workload variations, fluctuating from 0.2 to 5.1%. Average biases between repeated trials were contained within ± 1.1% for both TTs. In conclusion, using 40 and 100 km TTs containing 1 or 4 km bursts in power output, the present results indicate that (1) the CT can reliably be used by scientists to determine differences between research interventions; (2) the CT provides valid results of power output when data are being analyzed as a whole to derive one mean value of power output and; (3) variations in workload make it difficult to determine at any one time the veracity of the true power output produced by the athlete.

Effect of histamine-receptor antagonism on leg blood flow during exercise

Histamine mediates vasodilation during inflammatory and immune responses, as well as following endurance exercise. During exercise, intramuscular histamine concentration increases, and its production, appears related to exercise intensity and duration. However, whether histamine contributes to exercise hyperemia and promotes exercise blood flow in an intensity- or duration-dependent pattern is unknown. The purpose of this study was to compare leg blood flow across a range of exercise intensities, before and after prolonged exercise, with and without histamine-receptor antagonism. It was hypothesized that combined oral histamine H₁/H₂-receptor antagonism would decrease leg blood flow, and the effect would be greater at higher intensities and following prolonged exercise. Sixteen (7F, 9M) volunteers performed single-leg knee-extension exercise after consuming either placebo or combined histamine H₁/H₂-receptor antagonists (Blockade). Exercise consisted of two graded protocols at 20, 40, 60, and 80% of peak power, separated by 60 min of knee-extension exercise at 60% of peak power. Femoral artery blood flow was measured by ultrasonography. Femoral artery blood flow increased with exercise intensity up to 2,660 ± 97 mL/min at 80% of peak power during Placebo (P < 0.05). Blood flow was further elevated with Blockade to 2,836 ± 124 mL/min (P < 0.05) at 80% peak power (9.1 ± 4.8% higher than placebo). These patterns were not affected by prolonged exercise (P = 0.13). On average, femoral blood flow during prolonged exercise was 12.7 ± 2.8% higher with Blockade vs. Placebo (P < 0.05). Contrary to the hypothesis, these results suggest that histamine receptor antagonism during exercise, regardless of intensity or duration, increases leg blood flow measured by ultrasonography.NEW & NOTEWORTHY Leg blood flow during exercise was increased by taking antihistamines, which block the receptors for histamine, a molecule often associated with inflammatory and immune responses. The elevated blood flow occurred over exercise intensities ranging from 20 to 80% of peak capacity and during exercise of 60 min duration. These results suggest that exercise-induced elevations in histamine concentrations are involved in novel, poorly understood, and perhaps complex ways in the exercise response.