Clinical Scenario: Exertional heat stroke (EHS) is a potentially deadly heat illness and poses a significant health risk to athletes; EHS survival rates are near 100% if properly recognized and treated. Whole-body cold water immersion (CWI) is the most effective method for lowering body core temperature. Precooling (PC) with CWI before exercise may prevent severe hyperthermia or EHS by increasing the body’s overall heat storage capacity. However, PC may also alter athletes’ perception of how hot they feel or how hard they are exercising. Consequently, they may be unable to accurately perceive their body core temperature or how hard they are working, which may predispose them to severe hyperthermia or EHS. Clinical Question: Does PC with whole-body CWI affect thermal sensation (TS) or rating of perceived exertion (RPE) during exercise in the heat? Summary of Key Findings: In 4 studies, RPE during exercise ranged from 12 (2.0) to 20 (3.0), with no clinically meaningful differences between PC and control trials. TS scores ranged from 2 (1.0) to 8 (0.5) in control trials and from 2 (1.0) to 7.5 (0.5) during PC trials. Clinical Bottom Line: PC did not cause clinically meaningful differences in RPE or TS during exercise. It is unlikely that PC would predispose athletes to EHS by altering perceptions of exercise intensity or body core temperature. Strength of Recommendation: None of the reviewed studies (all level-2 studies with Physiotherapy Evidence Database scores ≥ 5) suggest that PC with CWI influences RPE or TS in exercising males.
Timothy M. Wohlfert and Kevin C. Miller
NiCole R. Keith, Daniel O. Clark, Timothy E. Stump, Douglas K. Miller and Christopher M. Callahan
An accurate physical fitness survey could be useful in research and clinical care.
To estimate the validity and reliability of a Self-Reported Fitness (SRFit) survey; an instrument that estimates muscular fitness, flexibility, cardiovascular endurance, BMI, and body composition (BC) in adults ≥ 40 years of age.
201 participants completed the SF-36 Physical Function Subscale, International Physical Activity Questionnaire (IPAQ), Older Adults’ Desire for Physical Competence Scale (Rejeski), the SRFit survey, and the Rikli and Jones Senior Fitness Test. BC, height and weight were measured. SRFit survey items described BC, BMI, and Senior Fitness Test movements. Correlations between the Senior Fitness Test and the SRFit survey assessed concurrent validity. Cronbach’s Alpha measured internal consistency within each SRFit domain. SRFit domain scores were compared with SF-36, IPAQ, and Rejeski survey scores to assess construct validity. Intraclass correlations evaluated test-retest reliability.
Correlations between SRFit and the Senior Fitness Test domains ranged from 0.35 to 0.79. Cronbach’s Alpha scores were .75 to .85. Correlations between SRFit and other survey scores were –0.23 to 0.72 and in the expected direction. Intraclass correlation coefficients were 0.79 to 0.93. All P-values were 0.001.
Initial evaluation supports the SRFit survey’s validity and reliability.
Ross H. Miller, Stacey A. Meardon, Timothy R. Derrick and Jason C. Gillette
Previous research has proposed that a lack of variability in lower extremity coupling during running is associated with pathology. The purpose of the study was to evaluate lower extremity coupling variability in runners with and without a history of iliotibial band syndrome (ITBS) during an exhaustive run. Sixteen runners ran to voluntary exhaustion on a motorized treadmill while a motion capture system recorded reflective marker locations. Eight runners had a history of ITBS. At the start and end of the run, continuous relative phase (CRP) angles and CRP variability between strides were calculated for key lower extremity kinematic couplings. The ITBS runners demonstrated less CRP variability than controls in several couplings between segments that have been associated with knee pain and ITBS symptoms, including tibia rotation–rearfoot motion and rearfoot motion–thigh ad/abduction, but more variability in knee flexion/extension–foot ad/abduction. The ITBS runners also demonstrated low variability at heel strike in coupling between rearfoot motion–tibia rotation. The results suggest that runners prone to ITBS use abnormal segmental coordination patterns, particular in couplings involving thigh ad/abduction and tibia internal/external rotation. Implications for variability in injury etiology are suggested.
Timothy J. Brindle, Jeri L. Miller, Maria K. Lebiedowska and Steven J. Stanhope
Predicting muscle fascicle length changes during passive movements may lead to a better understanding of muscle function. The purpose of this study was to experimentally compare fascicle length changes in the gastrocnemius during two-joint passive movements with a previously derived kinematic model based on anatomical measures from a cadaver. The ratio of passive ankle to knee motion was manipulated to generate medial gastrocnemius fascicle elongation and lateral gastrocnemius fascicle shortening. Ultrasound images from both heads of the gastrocnemius fascicles were acquired at 10° knee flexion increments and compared with this kinematic model. Our results suggest that the two-joint kinematic model from which we originally based our knee and ankle movements did not adequately reflect fascicle length changes during any of the movement conditions in this study. From our data, we propose that for every degree of ankle motion the medial and lateral gastrocnemius changes 0.42 mm and 0.96 mm, respectively, whereas changes of 0.14 mm and 0.22 mm are observed for the medial and lateral gastrocnemius, respectively, during knee movements.
Steven Malvasi, Brian Gloyeske, Matthew Johnson and Timothy Miller
Injury to the anterior cruciate ligament (ACL) is one of the most common orthopedic injuries in the United States, while injury to the patellar tendon (PT) is less common. A combined rupture to the ACL and PT is consequentially uncommon and increases the difficulty of a correct initial diagnosis. The purpose of this paper is to critically appraise the current peer-reviewed literature regarding multi-ligamentous knee injuries (MLKI) in sport.
A systematic review was undertaken to identify all relevant peer-reviewed articles regarding MLKI from March 1980 to January 2015. All articles pertaining to simultaneous rupture of the ACL and PT were included for review.
A total of 27 cases presented in 15 articles were used. Findings suggest that the combination of a palpable gap over the PT, a positive Lachman test, inability to complete terminal knee extension, and a superior position of the patella are clinical examination markers for a possible MLKI involving the ACL and PT.
Simultaneous rupture to the ACL and PT is incredibly rare within the sport population, making diagnosis and treatment of such injury challenging. A thorough examination of the extensor mechanism of the knee is important in making the proper diagnosis.
Michael G. Miller, Christopher C. Cheatham, William R. Holcomb, Rosealin Ganschow, Timothy J. Michael and Mack D. Rubley
No direct research has been conducted on the relationship between subcutaneous tissue thickness and neuromuscular electrical stimulation (NMES).
The purpose of this study was to determine the effects of subcutaneous tissue thickness on NMES amplitude and NMES force production of the quadriceps.
Simple fixed design, testing the independent variable of subcutaneous thickness (skinfold) groups with the dependent variables of NMES amplitude and force production.
Athletic Training Laboratory.
29 healthy women.
NMES to produce at least 30% of maximal voluntary isometric contractions (MVIC) of the quadriceps.
Main Outcome Measure:
Maximal NMES amplitude and percentage of MVIC using NMES.
A significant skinfold category difference F2,28 = 3.92, P = .032 on NMES amplitude was found. Post hoc revealed the thinnest skinfold category tolerated less amplitude compared to the thickest category. A significant correlation was found between NMES amplitude skinfold category R = .557, P = .002.
Higher NMES amplitudes are needed for the thickest skinfold category compared to the thinnest skinfold category.