Shoulder dynamic stability and shoulder range of motion in volleyball athletes.

Shoulder injuries are one of the most common injuries in athletics, especially the athletes who use overhead motions like volleyball hitters, quarterbacks in football, and baseball pitchers. Approximately 20% of all game and practice injuries were sustained in the shoulder; shoulder muscle strains (11%), shoulder tendinitis (7%), and shoulder subluxation (4%). Those shoulder muscle strain, tendinitis, and subluxation are caused by the glenohumeral joint multidirectional instability; the humeral head moves on the glenoid fossa excessively during the overhead motion due to the weakness of the shoulder and scapular muscles. The purpose of the study was to determine the shoulder internal rotation peak torque (PT) difference between the normal shoulder range of motion (ROM) and hyper-ROM group with 90° of shoulder abduction and 90° of elbow flexion. Twenty-one highly trained women volleyball athletes who were around Edmond and Oklahoma City area voluntary participated in the study and measured their active shoulder external rotation using the goniometer, as well as their shoulder internal concentric rotation peak torque by using the Biodex isokinetic dynamometer. There was no significant difference in shoulder internal rotation peak torque between the normal ROM and hyper-ROM with 90° of shoulder abduction and 90° of elbow flexion in this thesis study that indicated there was no shoulder dynamic stability difference in the both groups (F = 2.763, t (15) = .741, p = .115). Keywords: shoulder, stability, peak torque, range of motion, volleybal

Rapid Muscle Activation Changes Across a Competitive Collegiate Female Soccer Season

Objective: The purpose of this study was to examine the effects of a competitive soccer season on rapid activation properties of the knee extensors and flexors in Division II female soccer players. Methods: Eighteen collegiate female soccer players participated in the present study, however, due to injuries during the season a final sample of 16 players were included for study analysis. Participants performed two maximal voluntary isometric contractions (MVICs) of the knee extensors and flexors before, during, and at the end of a competitive college soccer season. Electromyography root mean square (EMG RMS; μV), rate of EMG rise (RER; %Peak EMG•s-1), and electromechanical delay (EMD; ms) were examined on both legs for the knee extensors and flexors. Results: EMG RMS at early time intervals (0-50, 0-100, and 50-100 ms) and RER at 0-75 ms for the knee extensors and flexors significantly increased from the pre-season to the end of the season (P ≤ 0.010-0.026, η2=0.36-0.81). EMD of the knee flexors significantly decreased at the mid-season and the end of the season compared to the pre-season (P \u3c 0.001, η2=0.95). Conclusions: These findings may have important implications for monitoring improvements on thigh neuromuscular activation and developing lower extremity injury prevention strategies during a competitive collegiate female soccer season

Motivation of Shoulder Surgery Patients for Rehabilitation

International Journal of Exercise Science 10(2): 234-245, 2017 Motivation can be a valuable construct during physical rehabilitation. Rehabilitation can be uncomfortable and painful, testing patients’ rehabilitation motivation and continued participation. Maintaining motivation throughout rehabilitation is important for patients to return to optimal joint motion and daily functioning. The purpose of this research project was to examine rehabilitation motivation after shoulder surgery (rotator cuff repairs, slap repairs, biceps tenodesis, acromioplasty, distal clavicle excision or combination). Persons who underwent shoulder surgery (December 2014 – April 2015) voluntarily participated in the study. The Self Regulation Questionnaire was used to assess patients’ self-regulation and motivation. Surveys were administered to participants during rehabilitation at appointments with the physician. This study revealed significant changes to participants’ self-regulation throughout the 16-week post shoulder surgical rehabilitation process. Significant increases were discovered when looking at patients’ attention to goals and employing strategies to meet those goals. Other main areas of increase included problem solving, planning rehabilitation outside of therapy and coping with challenging times in rehabilitation. Data allows researchers and health care professionals to evaluate the dynamics of motivation fluctuation during rehabilitation. In addition, data will allow researchers to identify areas of motivational concern to implement motivation techniques in order to aid patients through rehabilitation

Vertical Jump Performance as a Discriminator of Playing Ability in Collegiate Female Soccer Players

Previous studies have assessed the importance of physical characteristics to soccer playing ability by comparing performance-based outcomes between starters and non-starters. Starters are often considered the most skilled players on the team. These players get more playing time than non-starters and have been shown to achieve higher performance outcomes on intermittent fitness tests. However, it remains unclear whether starters can achieve higher performance outcomes on a countermovement vertical jump. PURPOSE: The purpose of this study was to investigate the efficacy of countermovement vertical jump height and peak power to discriminate between starters and non-starters in collegiate female soccer. METHODS: Twenty-seven collegiate female soccer players (age = 19.56 ± 1.28 years; height = 164.26 ± 5.74 cm; body mass = 66.65 ± 8.43 kg) were recruited to participate in the present study. All testing was completed during the 2021 preseason training period. The players were classified as starters (n = 12) or non-starters (n = 15) according to their average number of minutes played per game during the subsequent exhibition season. Each participant reported to the laboratory for a single visit where they performed three countermovement vertical jump tests on a jump mat. For each jump, participants stood on the mat with feet shoulder width apart and hands positioned on the hips. Participants were not allowed to take any steps prior to performing the vertical jump and a quick descending quarter-squat countermovement was allowed before the ascending takeoff phase. The participants were instructed to jump as explosively as possible with both feet at the same time and land on the jump mat in the starting position. Vertical jump height (cm) was estimated from the flight time recorded by the jump mat. Peak power output was estimated using a previously validated regression equation: peak power (W) = 51.9 × vertical jump height (cm) + 48.9 × body mass (kg) - 2007. Independent samples t-tests were used to compare vertical jump height and peak power between the starting and non-starting groups. RESULTS: Vertical jump height was significantly greater (P = 0.039) for the starters (38.60 ± 6.11 cm) compared to the non-starters (34.43 ± 3.75 cm). There was no significant difference (P = 0.448) between the starters (3076.72 ± 331.98 W) and non-starters (3182.23 ± 369.67 W) for peak power. CONCLUSION: These findings suggest that vertical jump height is an effective measure for discriminating between starters and non-starters in collegiate female soccer. Vertical jump characteristics are critical to a player’s performance on the field. Because the starters in this study were able to jump higher than the non-starters, vertical jump height may be an important parameter for identifying players with a high degree of soccer playing ability

An Examination of Estimated BMI and Perceived Wellness among Students at a Midsized Midwest University

Health is complex and the perception of individual wellness can be influenced by various factors. Students at a Midwestern university estimated their BMI, completed the Perceived Wellness Survey, and had their BMI calculated. Measured BMI was significantly higher than estimated [F(2,155) = 62.03, p = 0.001]. Associations existed between the measured constructs of psychological (r = -0.231; p = 0.004), spiritual (r = 0.248; p = 0.002), and estimated BMI. Data indicates that perceived body composition is related to wellness. False perception of body composition could lead to wellness deficiencies

Reliability of panoramic ultrasound imaging to simultaneously examine muscle size and quality of the hamstring muscles in young, healthy males and females

The purpose of this study was to examine the reliability of ultrasound (US) measures of cross-sectional area (CSA), muscle thickness (MT) and echo intensity (EI) of the hamstrings, with comparisons between males and females. In 20 healthy participants (10 males, 10 females), CSA, MT and EI were measured from panoramic US scans of the hamstrings on 2 separate days. The intra-class correlation coefficients and standard errors of measurement as a percentage of the mean for CSA, MT and EI ranged from 0.715 to 0.984 and from 3.145 to 12.541% in the males and from 0.724 to 0.977 and from 4.571 to 17.890% in the females, respectively. The males had greater CSAs and MTs and lower EIs than the females (p = 0.002–0.049), and significant relationships were observed between CSA and MT (r = 0.714-0.938, p ≤ 0.001–0.023). From an overall reliability standpoint, these findings suggest that panoramic US may be a reliable technique for examining muscle size and quality of the hamstrings in both males and females

Changes in Knee Extension and Flexion Maximal and Rapid Torque Characteristics During a Collegiate Women's Soccer Season

Akehi, K, Palmer, TB, Conchola, EC, Thompson, BJ, Kasl, A, Bice, M, and Unruh, S. Changes in knee extension and flexion maximal and rapid torque characteristics during a collegiate women\u27s soccer season. J Strength Cond Res 36(5):1389-1395, 2022—The purpose of this study was to assess the changes in maximal and rapid torque capacities of the knee extensor and flexor muscles over the course of a competitive season in NCAA Divsion II women\u27s soccer players. Eighteen female soccer athletes performed 2 maximal voluntary isometric contractions (MVICs) of the knee extensor and flexor muscles before, during, and at the end of the competitive season. Peak torque (PT) and rate of torque development (RTD) at 50 (RTD50), 200 (RTD200), and 100-200 (RTD100-200) milliseconds were extracted from each MVIC for both legs. The rapid (RTD50) to maximal force ratio (RTD:PT), hamstring-to-quadriceps (H:Q) strength ratio, and bilateral strength differences were also calculated. Results indicated that PT, RTD50, and RTD200 decreased 11-21% from the preseason to the midseason for the knee extensors (p \u3c 0.02) and RTD50 increased approximately 11% from the midseason to the end of season for the knee felxors (p \u3c 0.01). Rate of torque development-to-PT ratios for the knee extensors and flexors increased 12-25% at the end of the season (p \u3c 0.05). Also, H:Q strength ratios using PT, RTD50, and RTD200 increased 12.5-24% after the season started (p = 0.001-0.04). There were no bilateral strength differences (dominant vs. non-dominant limbs) across the season (p \u3e 0.05). These findings suggest that participation in a soccer season can change maximal and rapid torque production of the knee extensors and flexors. Coaches and clinicians should consider incorporating a season-long strength training and maintenance plan for soccer players with the aim to improve athletic performance and minimize the risk of musculoskeletal injuries to the lower extremities

Dorsiflexion, plantar-flexion, and neutral ankle positions during passive resistance assessments of the posterior hip and thigh muscles

Context: Passive straight-legged–raise (SLR) assessments have been performed with the ankle fixed in dorsiflexion (DF), plantar-flexion (PF), or neutral (NTRL) position. However, it is unclear whether ankle position contributes to differences in the passive resistance measured during an SLR assessment. Objective: To examine the influence of ankle position during an SLR on the passive torque, range of motion (ROM), and hamstrings electromyographic (EMG) responses to passive stretch of the posterior hip and thigh muscles. Design: Crossover study. Setting: Research laboratory. Patients or Other Participants: A total of 13 healthy volunteers (5 men: age = 24 ± 3 years, height = 178 ± 6 cm, mass = 85 ± 10 kg; 8 women: age = 21 ± 1 years, height = 163 ± 8 cm, mass = 60 ± 6 kg). Intervention(s): Participants performed 6 randomly ordered passive SLR assessments involving 2 assessments at each condition, which included the ankle positioned in DF, PF, and NTRL. All SLRs were performed using an isokinetic dynamometer programmed in passive mode to move the limb toward the head at 5°/s. Main Outcome Measure(s): During each SLR, maximal ROM was determined as the point of discomfort but not pain, as indicated by the participant. Passive torque and EMG amplitude were determined at 4 common joint angles (θ) separated by 5° during the final common 15° of ROM for each participant. Results: Passive torque was greater for the DF condition than the NTRL (P = .008) and PF (P = .03) conditions at θ3 and greater for the DF than NTRL condition (P = .02) at θ4. Maximal ROM was lower for the DF condition than the NTRL (P = .003) and PF (P \u3c .001) conditions. However, we found no differences among conditions for EMG amplitude (P = .86). Conclusions: These findings suggest that performing SLRs with the ankle positioned in DF may elicit greater passive torque and lower ROM than SLRs with the ankle positioned in PF or NTRL. The greater passive torque and lower ROM induced by the DF condition possibly were due to increased tension in the neural structures of the proximal thigh

Can isometric torque – time characteristics predict playing level in Division I American collegiate football players?

The purpose of this study was to determine if maximal and rapid isometric torque characteristics could discriminate starters from nonstarters in elite Division I American collegiate football players. Sixteen starters (mean ± SD: age = 20.81 ± 1.28 years; height = 184.53 ± 6.58 cm; and mass = 108.69 ± 22.16 kg) and 15 nonstarters (20.40 ± 1.68 years; 182.27 ± 10.52 cm; and 104.60 ± 22.44 kg) performed isometric maximal voluntary contractions (MVCs) of the leg flexor and extensor muscle groups. Peak torque (PT), rate of torque development (RTD), the time to peak RTD (TTRTDpeak), contractile impulse (IMPULSE), and absolute torque values (TORQUE) at specific time intervals were calculated from a torque-time curve. The results indicated significant and nonsignificant differences between starters and nonstarters for the early rapid leg flexion torque characteristics that included RTD, IMPULSE, and TORQUE at 30 and 50 milliseconds, and TTRTDpeak. These variables also demonstrated the largest effect sizes of all the variables examined (0.71-0.82). None of the leg extensor variables, leg flexion PT, or later leg flexion rapid torque variables (≥ 100 milliseconds) were significant discriminators of playing level. These findings suggest that the early rapid leg flexion torque variables may provide an effective and sensitive muscle performance measurement in the identification of collegiate football talent. Further, coaches and practitioners may use these findings when designing training programs for collegiate football players with the intent to maximize rapid leg flexion characteristics