Biomedical subjects

D Scott Davis

Publications and source records attributed to D Scott Davis.

3 recordsLinked to original sources

PubMed2006

The relationship of body segment length and vertical jump displacement in recreational athletes.

The purpose of this study was to determine if segmental skeletal length contributes to vertical jump (VJ) displacement in recreational athletes. Skeletal length measurements of the trunk, femur, tibia, and foot were obtained by palpation of bony landmarks and a standard tape measure. A pilot study (n = 10) examined the intratester and intertester reliability for each skeletal measure. The pilot investigation revealed fair to excellent intratester and intertester reliability. Seventy-eight recreational athletes (55 men and 23 women) with a mean age of 21.9 +/- 2.9 years participated in the investigation. Multiple regression analysis with gender as a categorical indicator variable revealed a significant gender difference; therefore, men and women were analyzed separately. Regression analysis for men identified foot length (p < 0.033, R(2) = 0.08) as the only significant skeletal length predictor of VJ displacement. None of the skeletal length measures was predictive of VJ displacement in women. Based on the results of this investigation, intrinsic skeletal length is not a strong predictor of VJ displacement in young adult recreational athletes.

Abdomen↗

PubMed2005

The effectiveness of 3 stretching techniques on hamstring flexibility using consistent stretching parameters.

This study compares the effects of 3 common stretching techniques on the length of the hamstring muscle group during a 4-week training program. Subjects were 19 young adults between the ages of 21 and 35. The criterion for subject inclusion was tight hamstrings as defined by a knee extension angle greater than 20 degrees while supine with the hip flexed 90 degrees . The participants were randomly assigned to 1 of 4 groups. Group 1 (n = 5) was self-stretching, group 2 (n = 5) was static stretching, group 3 (n = 5) was proprioceptive neuromuscular facilitation incorporating the theory of reciprocal inhibition (PNF-R), and group 4 (n = 4) was control. Each group received the same stretching dose of a single 30-second stretch 3 days per week for 4 weeks. Knee extension angle was measured before the start of the stretching program, at 2 weeks, and at 4 weeks. Statistical analysis (p < or = 0.05) revealed a significant interaction of stretching technique and duration of stretch. Post hoc analysis showed that all 3 stretching techniques increase hamstring length from the baseline value during a 4-week training program; however, only group 2 (static stretching) was found to be significantly greater than the control at 4 weeks. These data indicate that static stretching 1 repetition for 30 seconds 3 days per week increased hamstring length in young healthy subjects. These data also suggest that active self-stretching and PNF-R stretching 1 repetition for 30 seconds 3 days per week is not sufficient to significantly increase hamstring length in this population.

Adult↗

PubMed2004

Physical characteristics that predict functional performance in Division I college football players.

Strength and conditioning professionals who work with collegiate football players focus much of their time and effort on developing programs to enhance athletic performance. Although there has been much speculation, there is little scientific evidence to suggest which combination of physical characteristics best predicts athletic performance in this population. The purpose of this investigation was to examine the relationship among 6 physical characteristics and 3 functional measures in college football players. Data were gathered on 46 NCAA Division I college football players. The 3 response variables were 36.6-m sprint, 18.3-m shuttle run, and vertical jump. The 6 regressor variables were height, weight, percentage of body fat, hamstring length, bench press, and hang clean. A stepwise multiple regression analysis was performed to screen for variables that predict physical performance. Regression analysis revealed clear prediction models for the 36.6-m sprint and 18.3-m shuttle run. The results of this investigation will help strength and conditioning specialists better understand the variables that predict athletic performance in Division I college football players.

Anthropometry↗