TY - JOUR
T1 - Trunk muscle endurance measurement
T2 - Isometric contrasted to isokinetic testing in normal subjects
AU - Mayer, Tom
AU - Gatchel, Robert
AU - Betancur, Jaime
AU - Bovasso, Elizabeth
PY - 1995/4
Y1 - 1995/4
N2 - Study Design. This cohort study examined a sample (n = 152) of subjects tested for isokinetic lumbar strength and endurance, using novel endurance measures. Objectives. To validate a new lumbar sagittal isokinetic endurance testing protocol comparing reliability in a normal subject cohort with strength test reliability to include presentation of a gender-specific normative database, and then correlating the results to a Sorenson isometric endurance protacal. Summary of Background Data. The isometric Sorenson test has been virtually the only validated clinical tool for lumbar extensor trunk muscle endurance testing. using an exercise chair and permitting the subject to maintain the trurk horizontal against gravity for a single timed contraction. Alternative isokinetic sagittal lumbar performance measurement methodology bas been developed recently to measure trunk muscle endurance by determining declining work performance on repeated, reciprocal dynamic contractions. Method. We compared protocols performance measures, normative data, and reliability for the static isometric Sorenson test to three different sokinetic endurance measurements: The endurance ratio, final fatigue ratio, and recovery ratio. Subjects were tested on a sagittal Cybex TEF (Lumex, Inc., Ronkonkoma, NY) unit for a strength trial followed by an endurance trial. Subgroups also performed reliability and isometric endurance protocols. Results. We found an extremely low lest-retest correlation for the isometric Sorenson trunk extension test. All test-retest correlations for the correspondng isokinetic endurance measures were significant and markedly higher. Extensor muscle performance declined more substantially on all endurance measures then flexors and showed more variability. In contrast, trunk strength measures were more reliable and less variable than corresponding endurance measures. Moreover, correlations between the isometric Sorenson test and the isokinetic endurance measures were all negative; i.e., increases in Sorenson time are moderately correlated to greater decline in work performance. Conclusions. Reliability of the Sorenson isometric endurance test is unacceptably low, showing negative correlations to all isokinetic endurance tests for lumbar extensors. Isokinetic strength and endurance tests are for more reliable than isometric tests, with normative data showing more consistent results from men than women. Both genders display more substantial fatigue (and greater variability) in extensor endurance compared with flexor testing. Endurance measures are identified as human performance cognitive constructs, and reasons for greater variability than usually shown by trunk strength measurements are discussed.
AB - Study Design. This cohort study examined a sample (n = 152) of subjects tested for isokinetic lumbar strength and endurance, using novel endurance measures. Objectives. To validate a new lumbar sagittal isokinetic endurance testing protocol comparing reliability in a normal subject cohort with strength test reliability to include presentation of a gender-specific normative database, and then correlating the results to a Sorenson isometric endurance protacal. Summary of Background Data. The isometric Sorenson test has been virtually the only validated clinical tool for lumbar extensor trunk muscle endurance testing. using an exercise chair and permitting the subject to maintain the trurk horizontal against gravity for a single timed contraction. Alternative isokinetic sagittal lumbar performance measurement methodology bas been developed recently to measure trunk muscle endurance by determining declining work performance on repeated, reciprocal dynamic contractions. Method. We compared protocols performance measures, normative data, and reliability for the static isometric Sorenson test to three different sokinetic endurance measurements: The endurance ratio, final fatigue ratio, and recovery ratio. Subjects were tested on a sagittal Cybex TEF (Lumex, Inc., Ronkonkoma, NY) unit for a strength trial followed by an endurance trial. Subgroups also performed reliability and isometric endurance protocols. Results. We found an extremely low lest-retest correlation for the isometric Sorenson trunk extension test. All test-retest correlations for the correspondng isokinetic endurance measures were significant and markedly higher. Extensor muscle performance declined more substantially on all endurance measures then flexors and showed more variability. In contrast, trunk strength measures were more reliable and less variable than corresponding endurance measures. Moreover, correlations between the isometric Sorenson test and the isokinetic endurance measures were all negative; i.e., increases in Sorenson time are moderately correlated to greater decline in work performance. Conclusions. Reliability of the Sorenson isometric endurance test is unacceptably low, showing negative correlations to all isokinetic endurance tests for lumbar extensors. Isokinetic strength and endurance tests are for more reliable than isometric tests, with normative data showing more consistent results from men than women. Both genders display more substantial fatigue (and greater variability) in extensor endurance compared with flexor testing. Endurance measures are identified as human performance cognitive constructs, and reasons for greater variability than usually shown by trunk strength measurements are discussed.
KW - Endurance
KW - Fatigue
KW - Human performance testing
KW - Isokinetic
KW - Isometric
KW - Muscle
KW - Physical capacity
KW - Spinal disorders
KW - Trunk strength
UR - http://www.scopus.com/inward/record.url?scp=0028943841&partnerID=8YFLogxK
M3 - Article
C2 - 7644957
AN - SCOPUS:0028943841
SN - 0362-2436
VL - 20
SP - 920
EP - 926
JO - Spine
JF - Spine
IS - 8
ER -