CARDIOVASCULAR CONSEQUENCES OF COMPLETING A 160-KM ULTRA-MARATHON
Authors in the 2009, Volume 41, Number 1 issue of Medicine & Science in Sports & Exercise® conducted a study assessing the cardiovascular consequences of a 160-km ultra-marathon in a group of 25 athletes who completed the 2007 Western States 100-mile Endurance Run. The authors hypothesized that the ultra-endurance exercise would demonstrate decreases in cardiac function measured by traditional echocardiography and speckle tracking imaging. They also proposed that the changes would be related to changes in cardiac biomarkers and/or autonomic regulation. The athletes underwent testing before and after the ultra-marathon where left ventricular (LV) systolic and diastolic measurements were assessed with echocardiography, while myocardial peak strain and strain rate were analyzed using speckle tracking. Cardiac biomarkers measured were cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptide (NT-pro-BNP). Heart rate variability (HRV) indices were assessed using frequency and time domain measures. Significant decreases in LV function were demonstrated, as were peak strain. NT-pro-BNP concentrations were increased significantly post-race, while post-race cTnT was elevated in only five athletes. No significant alterations in HRV were seen post-race. Additionally, reductions in LV function were not associated significantly with changes in cardiac biomarkers and/or HRV. Bottom line: Participation in ultra-endurance events can result in reductions in LV function as well as cardiac biomarker release, but the mechanisms behind these changes remain unknown.
POTENTIAL APPLICATIONS OF PULSATING JOINT LOADING IN SPORTS MEDICINE
In the 2009, Volume 37, Number 1 issue of Exercise and Sport Sciences Reviews, the authors review the features of and potential usage in sports medicine of pulsating joint loading as a method of treating bone injuries in humans. Pulsating joint loading (PJL) applies mechanical loads to synovial joints, such as the elbow or knee, and enhances bone formation and bone wound healing throughout long bones, such as the ulna, tibia, and femur. The loads are imposed laterally to the epiphysis of a synovial joint and induce bone formation in the metaphysis and diaphysis of long bones and fracture healing. Typically, the loads are given at loading frequencies of 1-20 Hz for 3-5 min each day. Authors cite the following advantages of PBL: 1) It does not require direct contact with the site of bone formation or bone healing, 2) the apparatus for clinical use is inexpensive, 3) it is noninvasive, 4) it shows good compliance due to brief daily treatments, and 5) it has few side effects. Bottom line: Existing animal studies support the concept that PJL offers a unique load-driven therapy for strengthening bone and accelerating healing of injured bones that should be considered for use in sports medicine.
STRIDING TOWARD SOCIAL JUSTICE: THE ECOLOGIC MILIEU OF PHYSICAL ACTIVITY
In the 2009, Volume 37, Number 1 issue of Exercise and Sport Sciences Reviews, the authors critically evaluate evidence and trends in disparities research, within an ecologic framework, focusing upon multi-level environmental factors such as neighborhood and racial discrimination that influence physical activity. It is well recognized that the lowest levels of physical activity are in non-white populations and those with low socioeconomic status, position, or social class. Members of these groups have more stressful living conditions leading to health-compromising conditions associated with physical inactivity. The ecologic milieu is everything that contributes to the location and presence of healthy, physically active people living in a given environment. Multi-leveled environmental influences all contribute to the milieu. The micro-environment includes one's home, school, and work, all of which may or may not support physical activity. The meso-environment is the link that connects an individual's micro-environments, such as one's commute to work, which may not allow time or opportunity for physical activity. The macro-environment includes the policies and discrimination that may not favor physical activity opportunities and create hardship for lower socioeconomic status individuals. The authors give examples and suggestions for change within each of these environments to further describe the concepts. Bottom line: Taking the next steps in understanding the complex societal factors that impact physical activity patterns is vital in providing equitable opportunities for all to be healthy and physically active.