OBJECTIVE: To examine the intra-rater, inter-rater, and inter-instrumental reliability of the digitalized pinch muscle strength dynamometer. METHOD: Thirty normal subjects were examined for pinch strength, using both the Preston pinch gauge and the digitalized pinch dynamometer. The participants performed all pinch strength tests in the seated position as recommended by the American Society of Hand Therapists (ASHT). Three successive measurements were taken for each hand. The mean of the three trials was used for data analysis. The pinch strength tests performed used a repeated measure design and measurements were taken by each rater. RESULTS: The relationship between the Preston pinch gauge and the digitalized pinch dynamometer in pinch strength was reliable (the ICC were 0.821 and 0.785 in rater 1 and rater 2 respectively). The relationship between the first session and second session in pinch strength using the digitalized pinch dynamometer was reliable (the ICC were 0.872 and 0.886 in rater A and rater B respectively). The relationship between rater A and rater B in pinch strength using the digitalized pinch dynamometer was reliable (the ICC was 0.754). CONCLUSION: The pinch strength measurement using the digitalized pinch dynamometer is reliable within the rater and between raters. Thus, the Preston pinch gauge and the digitalized dynamometer measure grip strength equivalently, and can be used interchangeably.
Hand ; Hand Strength ; Muscle Strength ; Muscle Strength Dynamometer ; Pinch Strength ; Statistics as Topic

PURPOSE: Although single-radius (SR) designs have a theoretical advantage in quadriceps recovery following total knee arthroplasty (TKA), there has been a paucity of objective evaluation studies. MATERIALS AND METHODS: One hundred and twenty minimally invasive TKAs were prospectively randomized by a single surgeon into 2 groups: SR design TKA group and multi-radius design TKA group. Quadriceps force and power were assessed using a dynamometer, and clinical data were investigated preoperatively and 6 weeks, 3 months, 6 months and 1 year postoperatively. RESULTS: There were no differences between two groups in quadriceps recovery and clinical results throughout the follow-up period. Furthermore, the proportion of patients whose postoperative quadriceps force and power reached preoperative level was similar in both groups. CONCLUSIONS: Femoral component design itself would not significantly influence quadriceps recovery after TKA.
Arthroplasty ; Follow-Up Studies ; Humans ; Knee ; Muscle Strength Dynamometer ; Prospective Studies ; Prosthesis Design ; Quadriceps Muscle

OBJECTIVE: To investigate the reliability and validity of a new method for isometric back extensor strength measurement using a portable dynamometer. METHODS: A chair equipped with a small portable dynamometer was designed (Power Track II Commander Muscle Tester). A total of 15 men (mean age, 34.8±7.5 years) and 15 women (mean age, 33.1±5.5 years) with no current back problems or previous history of back surgery were recruited. Subjects were asked to push the back of the chair while seated, and their isometric back extensor strength was measured by the portable dynamometer. Test-retest reliability was assessed with intraclass correlation coefficient (ICC). For the validity assessment, isometric back extensor strength of all subjects was measured by a widely used physical performance evaluation instrument, BTE PrimusRS system. The limit of agreement (LoA) from the Bland-Altman plot was evaluated between two methods. RESULTS: The test-retest reliability was excellent (ICC=0.82; 95% confidence interval, 0.65–0.91). The Bland-Altman plots demonstrated acceptable agreement between the two methods: the lower 95% LoA was −63.1 N and the upper 95% LoA was 61.1 N. CONCLUSION: This study shows that isometric back extensor strength measurement using a portable dynamometer has good reliability and validity.
Back Muscles ; Female ; Humans ; Isometric Contraction ; Loa ; Male ; Methods* ; Muscle Strength Dynamometer ; Reproducibility of Results*

OBJECTIVE: The purpose of this study was to investigate the effect of early 3-D lumbar stabilization exercise to patients with chronic lumbago after microdiscectomy. METHOD: From March 2006 to January 2008, 234 patients(male: 104, female: 130) who underwent lumbar microdis- cectomy were performed CENTAUR lumbar stabilization exercise at 7days postoperatively, CENTAUR was used to measure strength of stabilization muscle. RESULT: As a result after lumbar stabilization exercise for 8weeks, lumbar muscular strength increased by 24% averagely at 8 angles(0 degrees, +45 degrees, -45 degrees, +90 degrees, -90 degrees, +135 degrees, -135 degrees, 180 degrees;+ clockwise, - counterclockwise)(p<0.05). It was possible for the microdiscectomy patients to practice lumbar stabilization exercise at 7days postoperatively. CONCLUSION: The early lumbar stabilization exercise was good effect on the muscular strength after microdiscectomy.
Humans ; Low Back Pain ; Muscle Strength Dynamometer ; Surgical Procedures, Minimally Invasive

OBJECTIVETo determine the anthropometric parameters and the isometric muscle strength in a working population sample in China, and to investigate the relationship between muscle strength and individual attributes, such as age, gender, height and weight.

METHODSThe study population consisted of 146 male and 47 female people including workers, administrators and college students. Four types of muscle strength, i.e., handgrip, arm lift, shoulder lift, and torso pull, were measured.

RESULTSLeft handgrip, right handgrip, arm lift, shoulder lift and torso pull of male workers were (42.07 +/- 7.20), (43.92 +/- 7.14), (26.79 +/- 4.64), (33.79 +/- 6.88), (88.56 +/- 17.98) kg, respectively while those of female workers were (21.29 +/- 5.09), (23.26 +/- 5.47), (13.29 +/- 3.37), (18.52 +/- 4.01), (41.06 +/- 12.04) kg, respectively. The female's strength was about 50% lower than the male's. The strength in the 40 approximately years old group was higher than that in other age groups. There were significant positive correlation between the gender and the isometric strength as well as between the body weight and the isometric strength. If the body weight served as the corrected parameter, there was no significant difference in the handgrip among the groups (P < 0.05), but the torso pull of male workers > college students > administrators. All relative muscle strengths except the torso pull were similar for all age groups.

CONCLUSIONThe body weight as the independent variable can be used for establishing the predictive equation of the muscle strength. Calculation of the relative muscle strength can relieve the interference of the body weight for the muscle strength.

Adolescent ; Adult ; Anthropometry ; Female ; Hand Strength ; physiology ; Humans ; Male ; Middle Aged ; Muscle Contraction ; physiology ; Muscle Strength ; physiology ; Muscle Strength Dynamometer ; Pilot Projects ; Transactional Analysis ; Work Capacity Evaluation

OBJECTIVE: To investigate the effects of asymptomatic back muscle weakness and spinal deformity on low back pain (LBP). METHODS: Sixty healthy subjects without LBP participated in this study. Radiography and an isokinetic/isometric dynamometer were used to respectively measure spinal scoliosis/lordosis and the strength of the trunk flexors/extensors. After 2 years, 48 subjects visited the hospital again and LBP episodes, its severity and the Korean version of the Oswestry Disability Index were assessed. Differences between the group with LBP and the group without LBP were evaluated and the association with LBP incidence and severity was determined. RESULTS: Sex, age, and trunk strength were significantly different in both group. Sex and age were significantly positive associated with LBP incidence. The isometric trunk flexor and extensor strength, maximum isokinetic trunk flexor and extensor strength were significantly and negatively associated with the LBP severity. The maximum isokinetic trunk extensor and maximum isometric trunk extensor strength was significantly negative associated with the LBP incidence. CONCLUSION: LBP incidence is associated with isometric and isokinetic trunk extensor weakness, whereas LBP severity is associated with age, sex, isokinetic trunk extensor and flexor weakness, isometric trunk extensor and flexor weakness.
Back Muscles ; Congenital Abnormalities ; Incidence ; Low Back Pain* ; Muscle Strength Dynamometer ; Muscle Weakness ; Muscles* ; Pilot Projects* ; Radiography ; Risk Factors*

OBJECTIVE: To investigate the effects of asymptomatic back muscle weakness and spinal deformity on low back pain (LBP). METHODS: Sixty healthy subjects without LBP participated in this study. Radiography and an isokinetic/isometric dynamometer were used to respectively measure spinal scoliosis/lordosis and the strength of the trunk flexors/extensors. After 2 years, 48 subjects visited the hospital again and LBP episodes, its severity and the Korean version of the Oswestry Disability Index were assessed. Differences between the group with LBP and the group without LBP were evaluated and the association with LBP incidence and severity was determined. RESULTS: Sex, age, and trunk strength were significantly different in both group. Sex and age were significantly positive associated with LBP incidence. The isometric trunk flexor and extensor strength, maximum isokinetic trunk flexor and extensor strength were significantly and negatively associated with the LBP severity. The maximum isokinetic trunk extensor and maximum isometric trunk extensor strength was significantly negative associated with the LBP incidence. CONCLUSION: LBP incidence is associated with isometric and isokinetic trunk extensor weakness, whereas LBP severity is associated with age, sex, isokinetic trunk extensor and flexor weakness, isometric trunk extensor and flexor weakness.
Back Muscles ; Congenital Abnormalities ; Incidence ; Low Back Pain* ; Muscle Strength Dynamometer ; Muscle Weakness ; Muscles* ; Pilot Projects* ; Radiography ; Risk Factors*

BACKGROUND: Cruciate-retaining (CR) prostheses have been considered to produce more physiologic femoral rollback, provide better proprioception, and result in better quadriceps recovery than posterior-stabilized (PS) prostheses after total knee arthroplasty (TKA). However, there are very few studies demonstrating these benefits in an objective manner. We investigated whether CR-TKA could result in (1) better quadriceps recovery; (2) a greater proportion of patients with beyond the preoperative level of recovery; and (3) better clinical outcomes than PS-TKA. METHODS: This was a prospective non-randomized comparative study on the results of CR-TKA and PS-TKA. CR prostheses were used in 51 knees and PS prostheses in 51 knees. Quadriceps force was measured with a dynamometer preoperatively and at postoperative 6 weeks, 3 months, and 6 months consecutively. The Knee Society score (KSS) and range of motion (ROM) were also evaluated. RESULTS: There were no differences between two groups in terms of the objective quadriceps force during the follow-up period. The proportion of patients with beyond the preoperative level of recovery was similar between groups. Moreover, the KSS and ROM were not significantly different between two groups. CONCLUSIONS: CR-TKA did not result in better quadriceps recovery than PS-TKA during the 6-month follow-up. In other words, PS-TKA could lead to comparable quadriceps recovery despite greater preoperative weaknesses such as more restricted ROM and more severe degenerative changes of the knee.
Arthroplasty, Replacement, Knee* ; Follow-Up Studies ; Humans ; Knee* ; Muscle Strength ; Muscle Strength Dynamometer ; Proprioception ; Prospective Studies ; Prostheses and Implants ; Quadriceps Muscle ; Range of Motion, Articular

OBJECTIVE: To evaluate the relationship between the cross sectional area (CSA) and isokinetic strength of the back muscles in patients with chronic low back pain. METHOD: Data of twenty-eight middle-aged patients with chronic back pain were analyzed retrospectively. CSAs of both paraspinal muscles and the disc at the L4-L5 level were measured in MRI axial images and the relative CSAs (rCSA: CSA ratio of muscle and disc) were calculated. The degree of paraspinal muscle atrophy was rated qualitatively. Isokinetic strengths (peak torque, peak torque per body weight) of back flexor and extensor were measured with the isokinetic testing machine. Multiple regression analysis with backward elimination was used to evaluate relations between isokinetic strength and various factors, such as CSA or rCSA and clinical characteristics in all patients. The same analysis was repeated in the female patients. RESULTS: In analysis with CSA and clinical characteristics, body mass index (BMI) and CSA were significant influencing factors in the peak torque of the back flexor muscles. CSA was a significant influencing factor in the peak torque of total back muscles. In analysis with rCSA and clinical characteristics, BMI was significant in influencing the peak torque of the back flexors. In female patients, rCSA was a significant influencing factor in the peak torque per body weight of the back flexors, and age and BMI were influencing factors in the peak torque of back flexors and total back muscles. CONCLUSION: In middle-aged patients with chronic low back pain, CSA and rCSA were influencing factors in the strength of total back muscles and back flexors. Also, gender and BMI were influencing factors.
Back Pain ; Body Mass Index ; Body Weight ; Female ; Humans ; Low Back Pain ; Magnetic Resonance Imaging ; Muscle Strength ; Muscle Strength Dynamometer ; Muscles ; Muscular Atrophy ; Retrospective Studies ; Torque

OBJECTIVE: To evaluate the relationship between the cross sectional area (CSA) and isokinetic strength of the back muscles in patients with chronic low back pain. METHOD: Data of twenty-eight middle-aged patients with chronic back pain were analyzed retrospectively. CSAs of both paraspinal muscles and the disc at the L4-L5 level were measured in MRI axial images and the relative CSAs (rCSA: CSA ratio of muscle and disc) were calculated. The degree of paraspinal muscle atrophy was rated qualitatively. Isokinetic strengths (peak torque, peak torque per body weight) of back flexor and extensor were measured with the isokinetic testing machine. Multiple regression analysis with backward elimination was used to evaluate relations between isokinetic strength and various factors, such as CSA or rCSA and clinical characteristics in all patients. The same analysis was repeated in the female patients. RESULTS: In analysis with CSA and clinical characteristics, body mass index (BMI) and CSA were significant influencing factors in the peak torque of the back flexor muscles. CSA was a significant influencing factor in the peak torque of total back muscles. In analysis with rCSA and clinical characteristics, BMI was significant in influencing the peak torque of the back flexors. In female patients, rCSA was a significant influencing factor in the peak torque per body weight of the back flexors, and age and BMI were influencing factors in the peak torque of back flexors and total back muscles. CONCLUSION: In middle-aged patients with chronic low back pain, CSA and rCSA were influencing factors in the strength of total back muscles and back flexors. Also, gender and BMI were influencing factors.
Back Pain ; Body Mass Index ; Body Weight ; Female ; Humans ; Low Back Pain ; Magnetic Resonance Imaging ; Muscle Strength ; Muscle Strength Dynamometer ; Muscles ; Muscular Atrophy ; Retrospective Studies ; Torque