Mark DeBeliso

Effects of a knee ligament injury prevention exercise program on impact forces in women.

Previous research suggests high impact forces generated during landings contribute to noncontact anterior cruciate ligament (ACL) injuries. In women, neuromuscular differences appear to modify the ability to dissipate landing forces when compared to men. This study examined peak vertical impact forces (Fp) and rate of force development (RFD) following a 9-week, low-intensity (simple jump-landing-jump tasks) and volume (number of foot contacts per workout) plyometric-based knee ligament injury prevention (KLIP) program. Female subjects were randomly assigned into control (n = 14) and treatment (n = 14) groups. Treatment subjects attended KLIP sessions twice a week for 9 weeks, and control subjects received no intervention. Ground reaction forces (Fp and RFD) generated during a step-land protocol were assessed at study onset and termination. Significant reductions in Fp (p = 0.0004) and RFD (p = 0.0205) were observed in the treatment group. Our results indicate that 9 weeks of KLIP training altered landing strategies in women to lower Fp and RFD. These changes are considered conducive to a reduced risk of knee injury while landing.

The Effects of a Commercially Available Warm-Up Program on Landing Mechanics in Female Youth Soccer Players

The purpose of this study was to examine lower extremity kinematics following implementation of the Sportsmetrics Warm-Up for Injury Prevention and Performance (WIPP) training program. The hypothesis was that there would be no difference in landing mechanics between 2 groups of female youth soccer players (9–11 years of age), with 1 group (Treatment) completing the 8-week–duration (2 days per week) WIPP program and the other serving as a Control group. We recruited 21 female youth soccer players. Treatment (n = 12) and Control (n = 9) groups were established. Using the Sportsmetrics Software for Analysis of Jumping Mechanics, we analyzed lower extremity movement during landing after subjects jumped off a 30.5-cm box and immediately went into a vertical jump. No significant changes in knee separation values were observed in the Treatment group after 8 weeks of WIPP training. The results indicate that 8 weeks of WIPP training did not significantly alter landing strategies.

The effect of resistance-training intensity on strength-gain response in the older adult.

This study examined how training intensity affects strength gains in older adults over an 18-week training period using nonperiodized, progressive resistance-training protocols. Untrained men and women participants were separated into 4 groups: group A (n = 17, 71.4 +- 4.6 years) performed 2 sets of 15 repetitions maximum (RM), group B (n = 13, 71.5 +- 5.2 years) performed 3 sets of 9 RM, group C (n = 17, 69.4 +- 4.4 years) performed 4 sets of 6 RM, group D (n = 14, 72.3 +- 5.9 years) served as controls. Training groups exercised 2 days/week performing 8 resistance exercises. Except for training intensity, the acute program variables were equated between groups. A 1RM for 8 exercises was obtained every 6 weeks. The total of 1RM for the 8 exercises served as the dependent variable. Results: repeated measures analysis of variance (ANOVA) and Scheffe post hoc revealed that, at 6 weeks, only groups B and C were significantly stronger than group D (p < 0.01). By weeks 12 and 18, all training groups were significantly stronger than controls (p < 0.01). However, no difference existed between groups A, B, and C at any time. The data suggests that, for protocols with equated acute program variables, strength gain is similar over 18 weeks for training intensities ranging from 6 to 15 RM in previously untrained older adults. When programming nonperiodized, progressive resistance exercise for novice senior lifters, in the initial phases of the program, a wide range of intensities may be employed with similar strength gain.

Detraining in the older adult: effects of prior training intensity on strength retention.

In this study, we assessed the influence of training intensity on strength retention and loss incurred during detraining in older adults. In a previous study, untrained seniors (age = 71.0 ± 5.0; n = 61) were randomly divided into 3 exercise groups and 1 control group. Exercise groups trained 2 days per week for 18 weeks with equivalent volumes and acute program variables but intensities of 2 X 15 repetitions maximum (RM), 3 X 9RM, or 4 X 6RM. Thirty of the original training subjects (age 71.5 ± 5.2 years) participated in a 20-week detraining period. A 1RM for 8 exercises was obtained pre- and posttraining and at 6 and 20 weeks of detraining. The total of 1RM for the 8 exercises served as the dependent variable. Analysis of variance procedures demonstrated significant increases in strength with training (44–51%; p > 0.05), but no group effect. All training groups demonstrated significant strength decreases at both 6 and 20 weeks of detraining independent of prior training intensity (all group average 4.5% at 6 weeks and 13.5% at 20 weeks; p > 0.04). However, total-body strength was significantly greater than pretraining values after the detraining period (all group average 82% at 6 weeks and 49% at 20 weeks; p > 0.001). The results suggest that when older adults participate in progressive resistance exercise for 18 weeks, then stop resistance training (i.e., detrain), strength losses occur at both 6 and 20 weeks of detraining independent of prior resistance training intensity. However, despite the strength losses, significant levels of strength are retained even after 20 weeks of detraining. The results have important implications for resistance-trained older adults who could undergo planned or unplanned training interruptions of up to 5 months.

Effect of functional isometric squats on vertical jump in trained and untrained men.

Berning, JM, Adams, KJ, DeBeliso, M, Sevene-Adams, PG, Harris, C, and Stamford, BA. Effect of functional isometric squats on vertical jump in trained and untrained men. J Strength Cond Res 24(9): 2285-2289, 2010-Functional isometrics (FIs) combine dynamic and isometric muscle actions and may hyperstimulate the nervous system leading to an enhanced postactivation potentiation (PAP) and improved subsequent performance. The purpose of this study was to investigate the impact of an FI squat on the countermovement vertical jump (CMVJ) in resistance trained and untrained men. Thirteen trained men (age: 22.8 ± 3.2 years, mass: 90.0 ± 16.3 kg, and height: 178.9 ± 7.1 cm) and 8 untrained men (age: 28.5 ± 5.9 years, mass: 101.5 ± 23.0 kg, and height: 177.0 ± 4.8 cm) participated. On separate days, subjects performed CMVJs after 2 different warm-up conditions. The warm-up conditions consisted of either 5 minutes of low-intensity cycling or 5 minutes of low-intensity cycling plus a 3-second FI squat with 150% of their 1 repetition maximum (1RM). A 2 × 3 repeated-measures analysis of variance with Bonferroni post hoc revealed that when comparing the 2 warm-up conditions in the trained subjects, a significant increase (p < 0.05) in CMVJ occurred at 4 minutes (2.4 cm, +5.1%) post-FI squat. This increase was maintained when subjects were retested at 5 minutes post (2.6 cm, + 5.5%). No significant difference in CMVJ was detected in the untrained group (p = 0.49). Results support the addition of an FI squat performed at 150% of 1RM to a low-intensity cycling warm-up to enhance PAP in resistance trained but not in untrained men as measured by CMVJ. Practically, adding functional isometrics to a warm-up scheme may significantly enhance acute, short-term power output in resistance trained men.

The Seated Medicine Ball Throw as a Test of Upper Body Power in Older Adults

Harris, C, Wattles, AP, DeBeliso, M, Sevene-Adams, PG, Berning, JM, and Adams, KJ. The seated medicine ball throw as a test of upper body power in older adults. J Strength Cond Res 25(8): 2344-2348, 2011—Practitioners training the older adult may benefit from a low-cost, easy-to-administer field test of upper body power. This study evaluated validity and reliability of the seated medicine ball throw (SMBT) in older adults. Subjects (n = 33; age 72.4 ± 5.2 years) completed 6 trials of an SMBT in each of 2 testing days and 2 ball masses (1.5 and 3.0 kg). Subjects also completed 6 trials of an explosive push-up (EPU) on a force plate over 2 testing days. Validity was assessed via a Pearson Product-Moment correlation (PPM) between SMBT and EPU maximal vertical force. Reliability of the SMBT was determined using PPMs (r), Intraclass correlation (ICC, R) and Bland-Altman plots (BAPs). For validity, the association between the SMBT and the EPU revealed a PPM of r = 0.641 and r = 0.614 for the 1.5- and 3.0-kg medicine balls, respectively. Test-retest reliability of the 1.5- and 3.0-kg SMBT was r = 0.967 and r = 0.958, respectively. The ICC values of the 1.5- and 3.0-kg SMBT were R = 0.994 and 0.989, respectively. The BAPs revealed 94% of the differences between day 1 and 2 scores were within the 95% confidence interval of the mean difference. Test-retest reliability for the EPU was r = 0.944, R = 0.969. The BAPs showed 94% of the differences between day 1 and 2 scores were within the 95% confidence interval of the mean difference, for both medicine ball throws. In conclusion, for the older adult, the SMBT appears to be highly reliable test of upper body power. Its validity relative to the maximal force exerted during the EPU is modest. The SMBT is an inexpensive, safe, and repeatable measure of upper body power for the older adult.

Physiological and Psychophysical Comparison Between a Lifting Task With Identical Weight but Different Coupling Factors

Adams, KJ, DeBeliso, M, Sevene-Adams, PG, Berning, JM, Miller, T, and Tollerud, DJ. Physiological and psychophysical comparison between a lifting task with identical weight but different coupling factors. J Strength Cond Res 24(2): 307-312, 2010-The objective of the revised NIOSH (National Institute for Occupational Safety and Health) lifting equation is to prevent or reduce lifting-related injuries. The coupling component of the equation relates to quality of the grip (i.e., hand-to-object interface) and can be rated good, fair, or poor. Good coupling is theorized to reduce lifting stress, whereas poor coupling is theorized to increase lifting stress. This study compared the physiological and psychophysical stress between a lifting task with identical weight but different coupling factors. Subjects (n = 21; 26 ± 6 years; 177.8 ± 7.8 cm; 73.9 ± 10.7 kg) transferred a milk crate or bag of dog food each weighing 12.5 kg back and forth from the floor to a table for 2, paced, 5-minute work bouts. Steady-state metabolic data were used to compare the lifting tasks. Results showed significantly higher oxygen consumption, caloric cost, heart rate, and rating of perceived exertion during the lifting task using the milk crate vs. the bag of dog food (p < 0.05). No difference in respiratory exchange ratio was observed (p > 0.05). In conclusion, a significantly higher metabolic cost and perceived exertion was observed when subjects performed a paced two-handed lifting task with good coupling factors than when using an object with poor coupling factors. When lifting stress is measured by metabolic cost and perceived exertion, these results are in contrast to expectations that a poor quality grip (i.e., poor coupling) would increase stress of a lifting task. Results of this study may help the work-place practitioner make decisions related to the use of the revised NIOSH lifting equation in the design and pacing of lifting-related tasks. Improved decision making may benefit productivity and enhance injury prevention in the workplace.

Optimal Timing for Post-Activation Potentiation in Women Collegiate Volleyball Players

Post-activation potentiation (PAP) has been shown to acutely amplify muscular power output and may be advantageous for athletes looking to improve performance. PAP may have an acute window of effectiveness between 2 to 20 min. With correct timing and implementation it may be possible to induce PAP in competitive situations. The purpose of this study was to examine the time frame of potentiation following a PAP warm-up in collegiate female volleyball players. In this study, nine female collegiate volleyball players completed three laboratory sessions over the course of 10 days. During the first session, the athlete’s 5-RM back squat was determined for subsequent use as the conditioning activity to initiate PAP. A repeated measures experimental design was then employed for Sessions 2 and 3 where half of the participants alternately performed either a dynamic or PAP warm-up prior to performing a standing long jump (SLJ) at 2, 6, 10, 14, and 18 min. A mixed-factor repeated measures ANOVA was used to determine the effects of the two warm-up strategies (PAP vs. dynamic) on standing long jump (SLJ) performance across time. There was a significant effect for time (p < 0.01) and warm-up strategy (p < 0.01). Bonferroni post hoc techniques determined that the SLJs that followed the PAP warm-up were significantly greater at 2 (4.8%), 6 (3.6%), and 10 (3.6%) min compared to SLJs post-dynamic warm-up (p < 0.05). However, those differences did not persist at 14 or 18 min (p > 0.05). Further analysis included non-parametric pairwise comparisons (Wilcoxon signed-rank tests) between the SLJ scores at 2, 6, 10, 14, and 18 min (PAP vs. dynamic). The non-parametric results were consistent with the parametric results. Within the parameters of this study, it is concluded that performing a 5-RM back squat induces a measureable PAP effect for up to 10 min.

The Prevalence of Depression and Concussions in a Sample of Active North American Semi-Professional and Professional Football Players.

Background Concussive events frequently occur in high impact sports such as North American football. The long term effects of concussive events on physical and psychological wellbeing are the focus of ongoing research. The purpose of this study was to determine if concussive events increase the incidence of depression in active semi-professional and professional North American football players. Methods An anonymous online survey was sent to 200 players to collect the following self-reported data: position played, years played, number of concussions sustained and subsequent depressive symptoms using the Center for Epidemiologic Studies Depression (CESD-R) scale. An independent T-test was used to determine differences in the number of concussive events in those with CESD-R scores <16 vs. ≥16, where scores ≥16 are indicative of a depressed state. Likewise, an independent T-test was used to compare CESD-R scores between players with ≥3 concussions vs. ≤2. Results Individuals with a CESD-R score ≥16, sustained a significantly greater number of concussions (3.8 vs. 1.6) than those who scored <16 (p < 0.001). Further analysis also revealed significantly higher CESD-R scores in players who had sustained ≥3 concussions (24.0 vs. 15.6) than those with ≤2 (p < 0.05). Conclusion Within the parameters of this study, players that were classified as depressed had sustained significantly more concussions compared to those who were not classified as depressed. Further, multiple concussive events (≥3) appears to increase symptoms of depression.

Differences in health promotion program participation, barriers and physical activity among faculty, staff and administration at a university worksite

Purpose – Health promotion programs (HPPs) are increasingly prevalent at universities due to the numerous documented benefits in other various work environments. However, universities are unique work environments with various job duties and responsibilities. Therefore, the purpose of this paper is to examine differences in participation in university HPPs among faculty, staff and administration. Further, barriers to participation were examined as well as an analysis of those meeting weekly physical activity (PA) recommendations. Design/methodology/approach – An electronic survey was sent to all employees at a large, metropolitan university (n=3,603), that inquired about participation in the university HPP in the last six months and their perceived barriers to participation. The International Physical Activity Questionnaire was used to assess PA amount, and thus, if the employee was meeting the weekly PA recommendations was determined. Findings – Results (n=308) indicated a difference in HPP participation ...