Isometric strength test consistency over time

1983 ◽  
Author(s):  
Terrence J. Stobbe ◽  
Ralph W. Plummer ◽  
Donald P. Shreves
1983 ◽  
Vol 27 (9) ◽  
pp. 790-793
Author(s):  
Terrence J. Stobbe ◽  
Ralph W. Plummer ◽  
Donald P. Shreves

Workmen's Compensation costs have become a major financial burden on industry. A significant part of these costs are the result of musculoskeletal injuries. One method of controlling these injuries is matching employees to jobs based on strength. Isometric strength testing has been shown to be an effective method of matching employee strength capability to job strength requirements. The use of screening test raises the question of test-retest consistency. This study was designed to determine the consistency of isometric strength test results over time. Thirteen student volunteer subjects (10m, 3F) participated in a testing protocol consisting of five strength tests performed a minimum of two times each at two week intervals. Four test sessions were held. An analysis of variance was used to identify week to week strength differences in the test population. Each of the five tests was analyzed separately and no significant week to week strength differences were found. This result further supports the validity of using isometric strength testing as a selection tool.


2014 ◽  
Vol 2 (11_suppl3) ◽  
pp. 2325967114S0014
Author(s):  
Gulcan Harput ◽  
Hasan Erkan Kılınc ◽  
Hamza Özer ◽  
Gül Baltacı ◽  
Carl G. Mattacola

Objectives: The aim of this study was to investigate quadriceps and hamstrings isometric strength at 4, 8 and 12 week time points following ACL Reconstruction (ACLR) and to document the strength changes of these muscles over time. The primary hypothesis was that there would be significant increases in quadriceps and hamstring muscle strengths between the 4th, 8th and 12th weeks following ACLR. The secondary hypothesis was that the quadriceps index would be higher than hamstring index at 12th week after ACLR. Methods: Thirty patients (Mean ± SD [age, 29.1±2.3yrs; weight, 77.3±13.2kg; height, 172.1±7.1cm; BMI, 21.2±3.5kg/m2, time to surgery: 7.1±7.2 months]) who underwent ACLR with Hamstring Tendon Autograft (HTG) were enrolled in this study. The isometric strength of quadriceps and hamstring muscles was measured on an isokinetic dynamometer at 60° knee flexion angle at 4th, 8th and 12th weeks after surgery. The recovery of quadriceps and hamstring muscles strength following rehabilitation was expressed as a Quadriceps Index (QI) and Hamstring Index (HI) and calculated with the following formula:[(maximum voluntary isometric torque of the involved limb / maximum voluntary isometric torque by uninvolved limb) × 100]. Torque output of the involved and uninvolved limbs and quadriceps and hamstring indexes were used for the statistical analysis. A repeated measures of ANOVA was used to determine the strength changes of quadriceps and hamstrings over time. Results: Quadriceps and Hamstrings strengths significantly increased over time for both involved (Quadriceps: F (2,46)=58.3, p<0.001, Hamstring: F (2,46)=35.7, p<0.001) and uninvolved limb (Quadriceps: F(2,46)=17.9, p<0.001, Hamstring: F(2,46)=56.9, p=0.001 ). Quadriceps strength was higher at 12th week when compared to the 8 and 4 week time points for the involved limb (p<0.001), and it was higher at 8th week when compared to 4 week time point for the involved limb (p<0.001). For the uninvolved limb, quadriceps strength was also higher at 12th week when compared to the 8 (p=0.02) and 4 week time point (p<0.001), and higher at 8 week when compared to the 4 week time point (p=0.02). Hamstring strength was higher at 12 week when compared to the 8 and 4 week time points (p<0.001) and it was higher at 8 week when compared to 4 week time point for the involved limb (p<0.001). For the uninvolved limb hamstring strength was also higher at 12 week when compared to 4 week time point (p=0.01). There was no significant difference between the 4 and 8 week time points (p>0.05) or between the 8 and 12 week time points (p=0.07). Quadriceps and hamstring indexes significantly changed from 4th weeks (QI:57.9, HI:54.4 ) to 8th weeks (QI:78.8, HI:69.9 ) and from 8th weeks to 12th weeks (QI:82, HI:75.7 ) (p<0.001); however, there was no difference between indexes at the 12-week time point (p=0.17). Conclusion: Isometric strength of quadriceps and hamstring muscles for the involved and uninvolved limb increased during the early period of ACLR. The results of this study could be a baseline for clinicians while prescribing a rehabilitation protocol for ACLR patients with HTG to better appreciate expected strength changes of the muscles in the early phase.


2015 ◽  
Vol 24 (4) ◽  
pp. 398-404 ◽  
Author(s):  
Gulcan Harput ◽  
H. Erkan Kilinc ◽  
Hamza Ozer ◽  
Gul Baltaci ◽  
Carl G. Mattacola

Context:There is lack of information related to quadriceps and hamstring strength recovery during the early period of rehabilitation after anterior cruciate ligament reconstruction (ACLR) using hamstring-tendon graft (HTG).Objective:To investigate quadriceps and hamstring isometric strength at 4-, 8-, and 12-wk time points after ACLR and to document the strength changes of these muscles over time.Design:Longitudinal study.Participants:24 patients (age 28.1 ± 8.1 y) who underwent unilateral single-bundle anatomic ACLR with 4-strand semitendinosus and gracilis tendon graft.Main Outcome Measures:The isometric strength of quadriceps and hamstring muscles was measured on an isokinetic dynamometer at a 60° knee-flexion angle 4, 8, and 12 wk after surgery.Results:Quadriceps and hamstring strength significantly increased over time for both the involved limb (quadriceps F2,46 = 58.3, P < .001; hamstring F2,46 = 35.7, P < .001) and uninvolved limb (quadriceps F2,46 = 17.9, P < .001; hamstring F2,46 = 56.9, P = .001). Quadriceps and hamstring indexes significantly changed from 4 wk (QI 57.9, HI 54.4) to 8 wk (QI 78.8, HI 69.9) and from 8 wk to 12 wk (QI 82, HI 75.7) (P < .001); however, there was no difference between indexes at the 12-wk time point (P = .17).Conclusions:The results of this study serve as a reference for clinicians while directing a rehabilitation protocol for HTG ACLR patients to better appreciate expected strength changes of the muscles in the early phase of recovery.


2019 ◽  
Vol 2 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Sunggun Jeon ◽  
William M. Miller ◽  
Minsoo Kang ◽  
Xin Ye

2018 ◽  
Vol 4 (1) ◽  
pp. e000365 ◽  
Author(s):  
Ben Ashworth ◽  
Patrick Hogben ◽  
Navraj Singh ◽  
Laura Tulloch ◽  
Daniel D Cohen

ObjectivesLower limb isometric tests are used to assess strength and strength asymmetries and monitor reductions in muscle force that may contribute to loss of performance and increase injury risk. Isometric tests in the upper body may be appropriate to monitor neuromuscular performance of the shoulder joint in sports involving contact and overhead actions. The aim of this study was to determine the reliability of a novel upper body isometric strength test.MethodsEighteen elite rugby players (age 22.4±4.6 years; body mass 95.5±13.4 kg) were tested on consecutive days. Maximal isometric contractions using both limbs against a force platform were assessed at three angles of abduction (180°, ‘I’; 135°, ‘Y’ and 90°, ‘T’), in a prone lying position. To evaluate interday reliability, intraclass coefficients (ICC) were calculated for mean net peak force (NPF) and highest NPF achieved in any trial (peak NPF). Intratrial variability was assessed using coefficient of variation (CV), and the standard error of measurement (SEM) was used to calculate minimal detectable change (MDC).ResultsInterday reliability for NPF was excellent in all test positions (ICC 0.94–0.98). The test demonstrated high absolute reliability values (SEM 4.8–10.8) and interday measurement error was below 10% in all test positions (CV 5.0–9.9%) except for the non-dominant arm I-position (CV 11.3%). Minimum detectable change was between 13.2 and 25.9 N.ConclusionThe Athletic Shoulder test demonstrated excellent reliability for each test position supporting its use as a reliable tool to quantify the ability to produce and transfer force across the shoulder girdle.


2010 ◽  
Vol 12 (2) ◽  
pp. 81-86 ◽  
Author(s):  
Jesper Augustsson ◽  
Magnus Bruno ◽  
Joakim Swärd

Author(s):  
Mark B. A. De Ste Croix

Despite a relatively limited understanding of the factors associated with strength development, advances in equipment, and increased understanding of growth and maturation issues, have provided new insights into paediatric muscle strength development. Strength testing of children is performed routinely by researchers to monitor the determinants and development of strength throughout childhood, and also by physiotherapists to assess the degree of muscle disability and to diagnose the rate of recovery. It is important for strength test administrators to be equipped with knowledge of the normal age and sex-associated variations in strength and the factors attributable to that variation. Over time, the use of differing techniques to adjust for body size has changed our perspective of the historical concept of the age- and sex-associated differences in muscle strength. Likewise, the development of more sophisticated techniques to determine muscle size and body composition has allowed researchers to explore the factors associated with the development of strength during growth with a greater degree of validity.


Sports ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 13 ◽  
Author(s):  
Paul James Read ◽  
Anthony Nicholas Turner ◽  
Richard Clarke ◽  
Samuel Applebee ◽  
Jonathan Hughes

Background: It has been suggested that altering the knee flexion angle during a commonly used supine isometric strength test developed with professional soccer players changes preferential hamstring muscle recruitment. The aim of this study was to examine the electromyography (EMG) knee joint-angle relationship during this test, as these data are currently unknown. Methods: Ten recreational male soccer athletes (age: 28 ± 2.4 years) were recruited and performed a supine isometric strength test on their dominant leg with the knee placed at two pre-selected flexion angles (30° and 90°). The surface EMG of the gluteus maximus, biceps femoris, semitendinosus, and medial gastrocnemius was measured, in addition to the within-session reliability (intraclass correlation coefficient (ICC) and coefficient of variation (CV)). Results: Within-session reliability showed large variation dependent upon the test position and muscle measured (CV% = 8.8–36.1) Absolute mean EMG activity and percentage of maximum voluntary isometric contraction (MVIC) indicated different magnitudes of activation between the two test positions; however, significant mean differences were present for the biceps femoris only with greater activation recorded at the 30° knee angle (% MVIC: 31 ± 9 vs. 22 ± 7; p = 0.002). These differences (30% mean difference) were greater than the observed typical measurement error (CV% = 13.1–14.3 for the 90° and 30° test positions, respectively). Furthermore, the percentage MVIC showed a trend of heightened activation of all muscles with the knee positioned at 30°, but there was also more within-subject variation, and this was more pronounced for the gluteus maximus (CV% = 36.1 vs. 19.8) and medial gastrocnemius (CV% 31 vs. 22.6). Conclusions: These results indicate that biceps femoris and overall posterior chain muscle activation is increased with the knee positioned at 30° of flexion; however, the 90° angle displayed less variation in performance within individual participants, especially in the gluteus maximus and medial gastrocnemius. Thus, practitioners using this test to assess hamstring muscle strength should ensure appropriate familiarisation is afforded, and then may wish to prioritise the 30° knee position.


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