Comparison of ballistic and static stretching on hamstring muscle length using an equal stretching dose.

The purpose of this investigation was to determine which stretching technique, static or ballistic, is most effective for increasing hamstring muscle length when delivered at the same stretching dose over a 4-week training program. A single-blind, randomized controlled trial design was used in this investigation. Thirty-two participants (16 women and 16 men) between the ages of 18 and 27 years participated in the study. All participants who had a pre-training knee extension angle of less than 20° were excluded from the study. Subjects were randomly assigned to one of 3 groups: ballistic stretching, static stretching, or control group. Participants in the experimental stretching groups (ballistic and static stretching) performed one 30-second stretch 3 times per week for a period of 4 weeks. Statistical analysis consisted of a 2-way analysis of variance (group × sex) with an a priori alpha level of 0.05. No interaction between group and sex was identified (p = 0.4217). The main effect of sex was not statistically significant (p = 0.2099). The main effect for group was statistically significant at p < 0.0001. Post hoc analysis revealed that both static and ballistic stretching group produced greater increases in hamstring length than the control group. The static stretching group demonstrated a statistically greater increase in hamstring muscle length than the ballistic stretching group. No injuries or complications were attributed to either stretching program.

Teaching professionalism: a survey of physical therapy educators.

This study examined the opinions of physical therapy faculty relative to teaching and fostering professionalism in entry-level physical therapy education. A paper-and-pencil survey was mailed to a random sample of 318 physical therapy educators across the United States. Of the 318 surveys mailed, 166 participants (response rate, 52%) completed and returned the survey. Descriptive analysis revealed that 98% of the physical therapy educators view professionalism as an important component of a physical therapy curriculum. Eighty-nine percent of the respondents expressed concern about the professional behaviors of one or more of their entry-level students; however, based on the frequency of negative behaviors, these concerns appear to be isolated to a small percentage of the students. The most frequent negative behaviors observed among entry-level physical therapy students included tardiness and lack of personal responsibility. Respondents identified clinical reasoning, integrity, and honesty as the three most important professional skills for a physical therapist. The three most common teaching methods used to foster professionalism included generic abilities, small group discussion, and related reading assignments. Professional socialization is clearly a concern among physical therapy faculty for a few entry-level physical therapy students; however, based on the results of this investigation, it appears that most entry-level physical therapy students are making a smooth transition to professional socialization. The information obtained from this investigation may be useful to allied health professionals and educators to help promote professionalism among entry-level students enrolled in professional programs.

Concurrent validity of four clinical tests used to measure hamstring flexibility.

The purpose of this study was to examine the concurrent validity of 4 clinical tests used to measure hamstring muscle length. A pilot study (N = 10) was conducted to determine the intratester reliability of 4 hamstring length measures: knee extension angle (KEA), sacral angle (SA), straight leg raise (SLR), and sit and reach (SR). The pilot investigation revealed good to excellent intratester reliability (intraclass correlation coefficient = 0.92-0.95) for each of the 4 tests. Eighty-one subjects (42 men and 39 women) participated in the main investigation. Subjects were randomly tested for each of 4 assessments of hamstring length. Concurrent validity was determined using linear regression, correlation, and kappa statistics. Correlation coefficients corresponding to the concurrent validity of the six combinations of the 4 clinical tests revealed poor to fair correlation (r = 0.45-0.65). The correlation coefficients for each pair from greatest to least were SR-SA= 0.65, SLR-SR = 0.65, KEA-SLR = 0.63, KEA-SR = 0.57, SLR-SA = 0.50, and KEA-SA = 0.45. Despite the common clinical use of these measures to assess hamstring length, these tests do not have sufficient concurrent validity to be used interchangeably or to assume that they each measure the same construct (hamstring length). Based on the results of this investigation and a review of the literature, the authors recommend that researchers, clinicians, and strength and conditioning specialists adopt the KEA test as the gold standard measure for hamstring muscle length.

Upper Limb Neural Tension and Seated Slump Tests: The False Positive Rate among Healthy Young Adults without Cervical or Lumbar Symptoms.

This study examined the false positive rate of the upper limb neural tension test (ULNTT) and seated slump test (SST) among healthy young adults with no history of cervical, lumbar, or peripheral symptoms. Eighty-four subjects (27 men and 57 women) with a mean age of 22.9 years participated in the investigation. All participants completed a screening questionnaire designed to exclude subjects with a history of cervical or lumbar spine pain or injury, or upper or lower extremity neurological symptoms. The ULNTT and the SST were performed on the left upper and lower extremity of each participant. Of the 84 participants tested, 73 (86.9%) were found to have a positive ULNTT at some point in the available range of elbow extension. Twenty-eight (33.3%) of the 84 subjects had a positive SST at some point in the available range of knee extension. The mean knee extension angle for those subjects with a positive SST was 15.1 degrees with a 95% confidence interval (CI) of 12.3 and 19.7 degrees . The mean elbow extension angle for those with a positive ULNTT was 49.4 degrees with a 95% CI of 44.8 and 54.0 degrees . The number of positive tests for both the ULNTT and the SST was found to be high in this sample of asymptomatic healthy young adults. Based on the results of this investigation, the authors suggest that the current criteria for determining a positive test for both the ULNTT and the SST should be examined using the proposed range of motion cut-off scores.

Variables associated with level of disability in working individuals with nonacute low back pain: a cross-sectional investigation.

STUDY DESIGN: Single-site, exploratory, cross-sectional design. OBJECTIVE: To identify variables associated with disability related to low back pain (LBP), as measured by the modified Oswestry Low Back Pain Disability Questionnaire (mOSW), in a sample of working adults with nonacute LBP. BACKGROUND: Compared to acute LBP, there is little information available in the literature to identify variables associated with LBP-related disability in working individuals with stage 2 and stage 3 LBP. METHODS: Data analyzed were from working individuals with nonacute LBP (n = 235). The response variable was dichotomized by mOSW score (less than 20 or 20 or greater), and the regressor variables included 27 self-report, sociodemographic, impairment-based, and kinematic measures used to assess individuals with LBP. Logistic regression was used to identify variables associated with mOSW. RESULTS: One hundred eleven subjects had a mOSW score of 20 or greater, and 124 subjects had a mOSW score of less than 20. Logistic regression analysis identified 4 variables associated with LBP-related disability (mOSW): duration of LBP (P = .006), numeric pain rating (P<.0001), Fear-Avoidance Beliefs Questionnaire physical activity subscale (P = .0007), and limits of stability movement velocity in the forward direction (P = .02). The best model had an R2(u) of 0.25. CONCLUSION: The odds of LBP-related disability (mOSW) in this sample of nonacute working individuals were found to increase with longer duration of LBP, higher numeric pain rating scores, higher Fear-Avoidance Beliefs Questionnaire physical activity subscale scores, and slower limits of stability movement velocity in the forward direction. The identification of limits of stability movement velocity is a novel finding that may support a link between sensorimotor balance deficits and disability in working individuals with nonacute LBP.

Correlation of single leg vertical jump, single leg hop for distance, and single leg hop for time.

OBJECTIVES: To determine the correlation among three functional tests: single leg vertical jump (SLVJ), single leg hop for distance (SLHD), and single leg hop for time (SLHT). DESIGN: Prospective correlational investigation. SETTING: University research laboratory. PARTICIPANTS: Forty healthy men (n = 19) and women (n = 21) between the ages of 18 and 30 (23.9 ± 2.0 years). MAIN OUTCOME MEASURES: SLVJ was measured using the Vertec. SLHD was measured using a standard tape measure. SLHT was measured over a 10-m course using a standard stopwatch. RESULTS: The strongest correlation was between SLHT and SLHD, -0.89 and -0.89 for dominant and non-dominant lower extremities (LE), respectively. The weakest pairwise correlation was between SLVJ and SLHT, -0.71 and -0.63 for dominant and non-dominant LE, respectively. The correlation between SLVJ and SLHD was 0.74 and 0.71 for dominant and non-dominant LE, respectively. CONCLUSION: There is a strong correlation between SLHT and SLHD, suggesting that each test measures similar constructs of function, while the modest correlation between SLVJ and SLHT suggest these two tests do not measure the same functional components, and could be paired as outcome measures for the clinical assessment of lower extremity function.

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.

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.

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.