Context: Muscular power output of the upper limb is a key aspect of athletic and sporting performance. Maximal power describes the ability to immediately produce power with maximal velocity at the point of release, impact, or takeoff, with research highlighting that the greater an athlete’s ability to produce maximal power, the greater the improvement in athletic performance. Despite the importance of upper-limb power for athletic performance, there is presently no gold-standard test for upper-limb force development performance. Objective: The aim of this study was to investigate the test–retest reliability of force plate–derived measures of the countermovement push-up in active males. Design: Test–retest design. Setting: Controlled laboratory. Participants: Physically active college athletes (age 24  y, height 1.79 [0.08] m, body mass 81.7 [9.9] kg). Intervention: Subjects performed 3 repetitions of maximal effort countermovement push-up trials on Kistler force plates on 2 separate test occasions 7 days apart. Main Outcome Measures: Peak force, mean force, flight time, rate of force development, and impulse were analyzed from the force–time curve. Results: No significant differences between the 2 trial occasions were observed for any of the derived performance measures. Intraclass correlation coefficient and within-subject coefficient of variation calculations indicated performance measures to have moderate to very high reliability (intraclass correlation coefficient = .88–.98), coefficient of variation = 5.5%–14.1%). Smallest detectable difference for peak force (7.5%), mean force (8.6%), and rate of force development (11.2%) were small to moderate. Conclusion: Force platform–derived kinetic parameters of countermovement push-up are reliable measurements of power in college-level athletes.
Gemma N. Parry, Lee C. Herrington, and Ian G. Horsley
Natalie Cook and Tamerah N. Hunt
Clinical Scenario: Concussions are severely underreported, with only 47.3% of high school athletes reporting their concussion. The belief was that athletes who were better educated on the signs and symptoms and potential dangers of concussion would be more likely to report. However, literature has shown inconsistent evidence on the efficacy of concussion education, improving reporting behaviors. Factors such as an athlete’s attitude, subjective norms, and perceived behavioral control have shown promise in predicting intention to report concussions in athletes. Focused Clinical Question: Do attitudes, subjective norms, and perceived behavioral control influence adolescent athletes’ intention to report? Summary of Key Findings: Three studies (1 randomized control and 2 cross-sectional surveys) were included. Across the 3 studies, attitudes, subjective norms, and perceived behavioral control positively influenced athletes’ reporting intention. The studies found that attitude toward concussion reporting and perceived behavioral control were the most influential predictors of reporting intention. Clinical Bottom Line: There is moderate evidence to suggest that positive attitudes, supportive subjective norms, and increased perceived behavioral control influence reporting intention in secondary school athletes. Strength of Recommendation: Grade B evidence exists that positive attitudes, supportive subjective norms, and increased perceived behavioral control positively influence concussion reporting intention in secondary school athletes.
Kaitlyn C. Jones, Evelyn C. Tocco, Ashley N. Marshall, Tamara C. Valovich McLeod, and Cailee E. Welch Bacon
Clinical Scenario: Low back pain is widely prevalent in the general population as well as in athletes. Therapeutic exercise is a low-risk and effective treatment option for chronic pain that can be utilized by all rehabilitation clinicians. However, therapeutic exercise alone does not address the psychosocial aspects that are associated with chronic low back pain. Pain education is the umbrella term utilized to encompass any type of education to the patient about their chronic pain. Therapeutic exercise in combination with pain education may allow for more well-rounded and effective treatment for patients with chronic nonspecific low back pain (NS-LBP). Clinical Question: Does pain education combined with therapeutic exercise, compared with therapeutic exercise alone, improve patient pain in adults with chronic NS-LBP over a 2- to 3-month treatment period? Summary of Key Findings: A thorough literature review yielded 8 studies potentially relevant to the clinical question, and 3 studies that met the inclusion criteria were included. The 3 studies included reports that exercise therapy reduced symptoms. Two of the 3 included studies support the claim that exercise therapy reduces the symptoms of chronic NS-LBP when combined with pain education, whereas one study found no difference between pain education with therapeutic exercise. Clinical Bottom Line: There is moderate evidence to support the use of pain education along with therapeutic exercise when attempting to reduce symptoms of pain and disability in patients with chronic NS-LBP. Educational interventions should be created to educate patients about the foundation of pain, and pain education should be implemented as a part of the clinician’s strategy for the rehabilitation of patients with chronic NS-LBP. Strength of Recommendation: Grade B evidence exists to support the use of patient education with therapeutic exercise for decreasing pain in patients with chronic NS-LBP.
Jessica St Aubin, Jennifer Volberding, and Jack Duffy
Clinical Question: How does early return to physical activity impact return-to-play recovery time in patients 5–30 years old after an acute concussion as compared to the current best practice of resting? Clinical Bottom Line: Based on the information gathered, there is moderate evidence to support the incorporation of light to moderate physical activity within 7 days after a concussion in order to decrease recovery time and symptoms.
Emily A. Hall, Dario Gonzalez, and Rebecca M. Lopez
Clinical Question: Does the medical model of organizational structure compared to either the academic or traditional models have a greater influence on job satisfaction and quality of life in collegiate athletic trainers? Clinical Bottom Line: Based on the quality of the person-oriented evidence available, the recommendation to adopt the medical model for athletic training staff would receive a Strength of Recommendation Taxonomy (SORT) grade of B.
Joerg Teichmann, Rachel Tan, Kim Hébert-Losier, Yeo Wee Kian, Shabana Jalal Din, Ananthi Subramaniam, Dietmar Schmidtbleicher, and C. Martyn Beaven
Context: Sensorimotor, proprioceptive, and neuromuscular programs are critical for the successful rehabilitation of injured athletes, and these decrease reinjury rates. Objective: To investigate the effects of an unexpected disturbance program (UDP) on balance and unilateral strength metrics in athletes with unilateral knee ligament injury. Design: A 3-week parallel-group experimental design consisting of 9 rehabilitation sessions. Setting: National Sports Institute. Participants: Twenty-one national-level athletes (age 21.4 [4.4] y, body mass 63.9 [10.8] kg, height 169.0 [10.2] cm) who had sustained a unilateral knee ligament injury. Intervention: An UDP program designed to evoke rapid sensorimotor responses was compared with traditional training and a nonexercise control group. Main Outcome Measures: Unilateral total, anteroposterior, and mediolateral sway with eyes open and closed and unilateral isometric strength. Results: Traditional exercises tended to outperform the UDP when unilateral balance testing was performed with eyes open; however, balance improvement following UDP tended to be greater in the eyes-closed condition. Significant strength gains in both the injured and uninjured legs were only observed following the UDP. This increase in unilateral isometric strength was 23.4 and 35.1 kg greater than the strength improvements seen in the traditional rehabilitation and control groups (P < .05). Conclusions: UDP could improve neural aspects of rehabilitation to improve rehabilitation outcomes by improving strength, sensorimotor function, and proprioception. Given the complementary adaptations, an UDP could provide an effective adjunct to traditional rehabilitation protocols and improve return-to-play outcomes.
Adam Jones, Richard Page, Chris Brogden, Ben Langley, and Matt Greig
Context: The influence of playing surface on injury risk in soccer is contentious, and contemporary technologies permit an in vivo assessment of mechanical loading on the player. Objective: To quantify the influence of playing surface on the PlayerLoad elicited during soccer-specific activity. Design: Repeated measures, field-based design. Setting: Regulation soccer pitches. Participants: Fifteen amateur soccer players (22.1 [2.4] y), injury free with ≥6 years competitive experience. Interventions: Each player completed randomized order trials of a soccer-specific field test on natural turf, astroturf, and third-generation artificial turf. GPS units were located at C7 and the mid-tibia of each leg to measure triaxial acceleration (100 Hz). Main Outcome Measures: Total accumulated PlayerLoad in each movement plane was calculated for each trial. Ratings of perceived exertion and visual analog scales assessing lower-limb muscle soreness were measured as markers of fatigue. Results: Analysis of variance revealed no significant main effect for playing surface on total PlayerLoad (P = .55), distance covered (P = .75), or postexercise measures of ratings of perceived exertion (P = .98) and visual analog scales (P = .61). There was a significant main effect for GPS location (P < .001), with lower total loading elicited at C7 than mid-tibia (P < .001), but with no difference between limbs (P = .70). There was no unit placement × surface interaction (P = .98). There was also a significant main effect for GPS location on the relative planar contributions to loading (P < .001). Relative planar contributions to loading in the anterioposterior:mediolateral:vertical planes was 25:27:48 at C7 and 34:32:34 at mid-tibia. Conclusions: PlayerLoad metrics suggest that playing surface does not influence mechanical loading during soccer-specific activity (not including tackling). Clinical reasoning should consider that PlayerLoad magnitude and axial contributions were sensitive to unit placement, highlighting opportunities in the objective monitoring of load during rehabilitation.
Stef Feijen, Angela Tate, Kevin Kuppens, Thomas Struyf, Anke Claes, and Filip Struyf
Context: The latissimus dorsi plays a major role in generating the propulsive force during swimming. In addition, stiffness of this muscle may result in altered stroke biomechanics and predispose swimmers to shoulder pain. Measuring the flexibility of the latissimus dorsi can be of interest to reduce injury. However, the reliability of such measurement has not yet been investigated in competitive swimmers. Objective: To assess the within-session intrarater and interrater reliability of a passive shoulder flexion range of motion measurement for latissimus dorsi flexibility in competitive swimmers. Design: Within-session intrarater and interrater reliability. Setting: Competitive swimming clubs in Flanders, Belgium. Participants: Twenty-six competitive swimmers (15.46 [2.98] y; 16 men and 10 women). Intervention: Each rater performed 2 alternating (eg, left-right-left-right) measurements of passive shoulder flexion range of motion twice, with a 30-second rest period in between. Main Outcome Measures: The intraclass correlation coefficients were calculated to assess intrarater and interrater reliability. Results: Interrater intraclass correlation coefficient ranged from .54 (95% confidence interval [CI], −.16 to .81) to .57 (95% CI, −.24 to .85). Results for the intrarater reliability ranged from .91 (95% CI, .81 to .96) to .94 (95% CI, .87 to .97). Conclusion: Results of this study suggest that shoulder flexion range of motion in young competitive swimmers can be measured reliably by a single rater within the same session.
Jefferson Fagundes Loss, Edgar Santiago Wagner Neto, Tatiane Borsoi de Siqueira, Aline Dill Winck, Laura Silveira de Moura, and Luiz Carlos Gertz
Trunk-flexor muscle strength plays a fundamental role in athletic performance, but objective measurements are usually obtained using expensive and nonportable equipment, such as isokinetic dynamometers. The aim of this study was to assess the concurrent validity of a portable, one-dimensional, trunk-flexor muscle strength measurement system (Measurement System) that uses calibrated barbells and the reliability of the measurements obtained using the Measurement System, by conducting test–retests. As a complementary assessment, the measurements obtained during a maximum contraction test performed by a group of 15 subjects were also recorded. Four conditions were assessed: repeatability, time reproducibility, position reproducibility, and subject reproducibility. The results demonstrate that both the concurrent validity and the measured reliability (intraclass correlation coefficient > .98) of the Measurement System are acceptable. The Measurement System provides valid and reliable measures of trunk-flexor muscle strength.
Matheus Lima Oliveira, Isabela Christina Ferreira, Kariny Realino Ferreira, Gabriela Silveira-Nunes, Michelle Almeida Barbosa, and Alexandre Carvalho Barbosa
Context: Strength assessment is essential to prescribe exercise in sports and rehabilitation. Low-cost valid equipment may allow continuous monitoring of training. Objective: To examine the validity of a very low-cost hanging scale by comparing differences in the measures of peak force to a laboratory grade load cell during shoulder abduction, flexion, extension, and internal and external rotations. Design: Analytical study. Participants: Thirty-two healthy subjects (18 women, age 26  y, height 172  cm, mass 69  kg, body mass index 23  kg/m2). Main Outcome Measures: The dependent variable was the maximal peak force (in kilogram-force). The independent variable was the instrument (laboratory grade load cell and hanging scale). Results: No differences were observed while comparing the results. The intraclass correlation coefficients1,1 ranged from .96 to .99, showing excellent results. The Cronbach alpha test also returned >.99 for all comparisons. The SEM ranged from 0.02 to 0.04 kgf, with an averaged SD from 0.24 to 0.38 kgf. The correlation was classified as high for all tested movements (r > .99; P < .001), with excellent adjusted coefficients of determination (.96 < r 2 < .99). Bland–Altman results showed high levels of agreement with bias ranging from 0.27 to 0.48. Conclusions: Hanging scale provides valid measures of isometric strength with similar output measures as laboratory grade load cell.