The Effect of High Intensity Interval Run Training on Cross-sectional Area of the Vastus Lateralis in Untrained College Students.

Aerobic cycling has been repeatedly shown to induce hypertrophy in skeletal muscle across a variety of populations, while there has been a lack of investigation into the impact of running upon hypertrophy. An increasingly popular model of aerobic exercise is high-intensity interval training (HIIT); in addition to its positive impact upon cardiovascular health, HIIT may be sufficient for inducing significant muscular hypertrophy. Therefore, the purpose of this investigation was to examine the influence of a high-intensity interval running protocol upon hypertrophy of the vastus lateralis in an untrained, young population. Twelve recreationally active university students (Male: 2; Female: 10; 19.9±0.5 yr.; 169.8±1.9 cm; 63.8±2.3 kg; VO2max: 42.1±1.6 ml•kg-1min-1) completed 24.5±0.6 sessions of high-intensity interval run training over 10 weeks. The protocol consisted of four sets of 4 minutes running at 90-95% HRmax followed by 3 minutes active rest at 70% HRmax. Relative and absolute aerobic capacity increased 5.2±2.2% and 6.0±2.3% respectively as a result of the intervention (p< 0.05). Cross-sectional area (CSA) of the vastus lateralis was measured via panoramic ultrasound imaging pre- and post-intervention. Following the protocol, CSA of the intervention group was 10.6±2.7% greater (p< 0.05), while that of the control group did not change. This is the first data to demonstrate hypertrophy of the vastus lateralis in a young population following a running protocol. These data support the existing body of evidence suggesting aerobic exercise to be an effective mode of improving cardiorespiratory fitness as well as increasing whole muscle size of the quadriceps.

Occupational Sitting and Physical Activity Among University Employees.

The prevalence of overweight and obese in the U.S. has been thoroughly documented. With the advent of inactivity physiology research and the subsequent interest in sedentary behavior, the work environment has come under closer scrutiny as a potential opportunity to reverse inactivity. Therefore, the purpose of this study was to determine the sitting and physical activity (PA) habits among different classifications of university employees. University employees (n=625) completed an online survey based on the Occupational Sitting and Physical Activity Questionnaire (OSPAQ). Participants were instructed to describe time spent sitting, standing, walking, and in heavy physical labor during the last seven days, along with the number of breaks from sitting taken per hour. To establish habitual patterns of PA outside of work, employees recalled their participation in structured PA in the past seven days. Prior to data analysis, employees were categorized as Administration, Faculty, Staff, or Facilities Management. Statistically significant differences were found among employee classifications for min sit/d, p<.001; min stand/d, p<.001; min walk/d, p<.001; and min heavy labor/d, p<.001. No significant differences were found for breaks/h from sitting, p=.259 or participation in structured PA, p=. 33. With the exception of facilities management workers, university employees spent 75% of their workday seated. In conjunction with low levels of leisure time PA, university employees appear to be prime candidates for workplace interventions to reduce physical inactivity.