Isokinetic Trunk Muscle Strength Research Articles

Assessment of Isokinetic Trunk Muscle Strength and Fatigue Rate in Individuals after Bariatric Surgery.

Background and Objectives: Lean body mass loss after bariatric surgery (BS) is remarkable, despite an effective long-term mass reduction and significant declines in comorbidities. A person's functional capacity is adversely affected when their skeletal muscle strength declines by up to 30%. This study aimed to assess the isokinetic trunk muscle strength and fatigue rate in individuals after BS. Materials and Methods: This study included fifty-eight patients, both male and female, ranging in age from 19 to 45. Twenty-seven individuals had BS and twenty-seven healthy people served as the control group. The primary outcomes were the measurement of the concentric and eccentric isokinetic muscle strength of the trunk flexor and extensor muscles. An isokinetic dynamometer (Biodex Rehabilitation and Testing System 3) was used for the assessment of the isokinetic muscle strength. Noraxon EMG was used to determine a secondary outcome, which was the median frequency slop (MF/time) and root mean square slop (RMS/time) of the lumbar erector spinea muscle at 50% of the Maximum Voluntary Isometric Contraction (MVIC). Outcome measures were assessed for both groups. Results: Compared to the control group, the bariatric group showed a lower mean value of both concentric and eccentric isokinetic muscle strength for the flexor and extensor trunk muscles (p < 0.05). In terms of the EMG fatigue rate, the RMS slope increased significantly more than that of the control group, while the MF slope decreased (p > 0.05). Conclusions: The current study found that, in comparison to the healthy subjects, the BS group showed reduced levels of fatigue and isokinetic strength in the trunk muscles. Based on these results, it is recommended that individuals who underwent BS take part in tailored rehabilitation programs to avoid potential musculoskeletal issues in the future.

Relationship between Isokinetic Trunk Muscle Strength and Return to Sports Competition after Conservative Therapy in Fresh Cases of Lumbar Spondylolysis: A Retrospective Observational Study.

This study aimed to clarify the relationship between isokinetic trunk muscle strength and return to sporting activities in fresh cases of lumbar spondylolysis treated with conservative therapy. Patients included a total of ten men (age: 13.5 ± 1.7) who were instructed by their attending physicians to stop exercising and who met the eligibility criteria. Isokinetic trunk muscle strength was measured immediately after exercising for the first time (First) and one month (1M). Flexion and extension and maximum torque/body weight ratio were significantly lower First compared to 1M at all angular velocities (p < 0.05). Maximum torque generation time was significantly lower for First at 120°/s and 180°/s than at 1M (p < 0.05). Correlations with the number of days to return to sports competition were detected at 60°/s for maximum torque generation time (p < 0.05, r = 0.65). Following conservative treatment for lumbar spondylolysis, it was considered necessary to focus on trunk flexion and extension muscle strength and contraction speed of trunk flexors at the beginning of the exercise period. It was suggested that trunk extension muscle strength in the extension range might be one of the critical factors for returning to sports.

Assessment of isokinetic trunk muscle strength and its association with health-related quality of life in patients with degenerative spinal deformity

BackgroundA considerable portion of the elderly population are increasingly afflicted by degenerative spinal deformity (DSD), which seriously affects patient health-related quality of life (HRQoL). HRQoL index is used across many studies to show correlations between radio-graphical alignment, disability, and pain in patients with DSD. However, imaged structural deformity represents only one aspect for consideration, namely, the disability effect of DSD. We assessed the isokinetic strength of trunk muscle in patients with degenerative spinal deformity (DSD), and investigated its relationship with HRQoL.MethodsIn total, 38 patients with DSD (DSD group) and 32 healthy individuals (control group) were recruited. Both groups were homogeneous for age, weight, height and body mass index (BMI). Assessments were performed using the isokinetic dynamometer IsoMed-2000; trunk extensor, flexor strength and flexion/extension (F/E) ratios were explored concentrically at speeds of 30°, 60° and 120° per second. The grip strength of both hands was measured using a hand-held dynamometer. Visual analogue scale (VAS) scores, the Oswestry Disability Index (ODI), a Roland-Morris disability questionnaire (RDQ), and a 36-item Short Form Health Survey (SF-36) evaluated patient HRQoL. Correlations between trunk strength and HRQoL were analyzed.ResultsWhen compared with the control group, the DSD group showed lower trunk extensor strength at three velocity movements, and higher F/E ratios at 60° and 120°/s (p < 0.05). Both groups exhibited similar trunk flexor strength and grip strength (p > 0.05). In DSD group, trunk extensor strength at 60°/s was negatively associated with ODI and RDQ (p < 0.05). A negative relationship between trunk flexor strength at 120°/s and ODI was also recorded (p < 0.05). In addition, trunk extensor strength at 60°/s and trunk flexor strength at 120°/s were positively correlated with physical functioning and role-physical scores according to the SF-36 (p < 0.05).ConclusionsWe identified isolated trunk extensor myopathy in DSD, which causes an imbalance in trunk muscle strength. Isokinetic trunk extensor strength at 60°/s and trunk flexor strength at 120°/s can predict disability, and decrease physical HRQoL in DSD patients.

The relationship between isokinetic trunk and upper limb muscle strength and respiratory function and respiratory muscle strength: a cross-sectional study

article: The relationship between isokinetic trunk and upper limb muscle strength and respiratory function and respiratory muscle strength: a cross-sectional study - Medicina dello Sport 2020 December;73(4):635-51 - Minerva Medica - Journals

Isokinetic evaluation of the trunk muscle strength in housewives with fibromyalgia: a cross-sectional study

BackgroundIt is known that physical activity and muscular performance are reduced in fibromyalgia (FM) syndrome. This study aims to compare the performance of trunk muscles in women with FM and healthy controls and evaluate the correlation between trunk muscle strength and FM severity.MethodsForty-six patients with FM and 42 age- and body mass index-matched healthy housewives without FM were included in the FM and control groups, respectively. The Fibromyalgia Impact Questionnaire (FIQ) was used for the assessment of FM severity. The pain intensity was evaluated using the visual analogical scale (VAS). An isokinetic dynamometer was used to measure the isokinetic trunk muscle strength. The peak torque (PT) values were recorded. The psychological status of the patients was evaluated using the Beck Depression Inventory.ResultsThere was no statistically significant difference in terms of age, BMI, and BDI scores in two groups (p > 0.05, for all). The isokinetic trunk extensor PT values were significantly lower in the FM group (p = 0.002 for 60°/s, and p < 0.001 for 90°/s and 120°/s) than control group. There was a statistically significant negative correlation between FIQ score and isokinetic extensor muscle parameters.ConclusionThe results indicate that trunk extensor muscles were significantly weaker in FM patients. Trunk extensor muscle strength decreased as FM severity increased in FM patients.

Reply to the letter to the editor of L. Russo et al. concerning “Relationship between sagittal spinal curves geometry and isokinetic trunk muscle strength in adults” by W. Elsayed, A. Farrag, Q. Muaidi, N. Almulhim (2018) Eur Spine J 27:2014–2022

Reply to the letter to the editor of L. Russo et al. concerning “Relationship between sagittal spinal curves geometry and isokinetic trunk muscle strength in adults” by W. Elsayed, A. Farrag, Q. Muaidi, N. Almulhim (2018) Eur Spine J 27:2014–2022

Relationship between sagittal spinal curves geometry and isokinetic trunk muscle strength in adults.

Sagittal spinal deviation has been reported to be a significant musculoskeletal problem affecting both genders and could develop at any age. Factors triggering this issue are still not well defined. The purpose of this study was to investigate the relationship between sagittal spine angles and isokinetic peak, average torque, and power of trunk muscles in asymptomatic adults. A convenient sample of 79 subjects with asymptomatic spine participated in this study. Thoracic and lumbar curves angles were measured using the Formetric 4D device. Thoracolumbar (T/L) ratio was calculated as an indicator of spine balance. Isokinetic peak and average torque and average power for trunk flexors and extensors were measured at 60°/s in seated and semi-standing test positions. Lumbar curve angle was moderately inversely correlated (p<0.001) with peak extension torque (ρ=-0.532 and -0.495 in seated and semi-standing positions, respectively) and peak flexion torque (ρ=-0.604 and -0.542 in seated and semi-standing positions, respectively). The T/L ratio was found to be significantly associated (p<0.001) with trunk extension torque (ρ=0.422 and 0.378 in seated and semi-standing positions, respectively) and trunk flexion torque (ρ=0.396 and 0.321 in seated and semi-standing positions, respectively). Similarly, average torque and power measurements were significantly correlated with lumbar curve angle and T/L ratio. Sagittal spine balance is associated with trunk muscles strength in adults, particularly, the lumbar spine muscles. Therefore, assessment of sagittal spinal balance and trunk muscles strength should be taken into consideration when designing rehabilitation programs for correction of sagittal spine curvature.

Effects of Long Term Periodization Training in Korean Male Elite Golfers

[Purpose] The purpose of this study was to develop the periodization training for elite golfers and investigate the effect of the program for elite golfers. [Methods] Eighteen male participants were divided into training group (TG: n=8) and control group (CG: N=10). The periodization consists of flexibility and strength training and conducted for 20weeks. To examine the effects of training program, physical fitness (isometric muscle strength, flexibility, isotonic maximum strength, muscle power, muscle endurance, isokinetic trunk muscle strength) and driver performance (launch angle, club head speed, ball speed, and carry distance of the driver shot) were measured after 20 weeks of training. [Results] Back muscle strength, shoulder flexibility, isotonic maximum strength, muscle power, club-head speed, ball speed, carry distance showed significant interaction. [Conclusion] These results suggest that periodization training for 20-weeks turned out to be an effective in improving physical fitness and driver performance in Korean elite golfers. Therefore, not only during the preparation period but also the competition period, scientific physical training should be maintained in order to improve the physical function and driver performance.

Effect of unilateral exercise on spinal and pelvic deformities, and isokinetic trunk muscle strength.

[Purpose] The purpose of this study was to collect basic data regarding the prevention of spinal and pelvic deformities by investigating the spinal shape and muscular function characteristics of imbalance reduction and functional improvement following asymmetric activities. [Subjects and Methods] The subjects were 14 archery athletes who mostly perform unilateral motion with spinal and pelvic pain, and 19 healthy subjects. All the participants were evaluated using spinal structure analysis and for 60°/sec isokinetic muscular strength of the trunk. [Results] Between the two groups, there were significant differences in the interaction effect of trunk inclination deformities, and flexor and extensor 60°/sec isokinetic muscular strength of the trunk. Also, the main effects of gender comparison showed significant differences in the trunk inclination deformities, pelvic rotation deformities, lordosis angles, and flexor and extensor 60 ˚/sec isokinetic muscular strengths of the trunk. [Conclusion] The basic data obtained in this study can be used to help develop a strategic exercise program for improving unilateral movement and malalignment of the spine and pelvis.

A study of isokinetic trunk and knee muscle strength in patients with chronic sciatica

To evaluate trunk and knee muscle strength in patients with chronic sciatica in order to optimize the program of management in a rehabilitation setting. This is a prospective study which included 68 subjects. The first group (G1) comported 28 patients with right-side chronic sciatica. The second group (G2) comported 40 healthy controls. The strength of both trunk and knee muscles was evaluated by the isokinetic dynamometer. Quadriceps and hamstring muscle strength were evaluated at concentric velocities of 60 and 120°/s and the trunk muscles were evaluated at concentric velocities of 60 and 90°/s. The two groups were comparable. The peak torque values for the trunk flexors were lower in the group G1 ( P < 0.002 and P = 0.01, respectively at 60° and 90°). Similarly, the peak torque values for the trunk extensors was lower in this group ( P < 0.001 and P = 0.001, respectively at angular velocities of 60° and 90°). The deficit was higher in the group of the extensor muscles. The peak torque values for the right quadriceps and hamstrings at angular velocities of 60 and 120°/s were also lower in group G1. The differences were statistically significant ( P < 0.001). In G1, the quadriceps and hamstrings were significantly weaker on the sciatica side than on the unaffected side. The isokinetic muscle strength evaluation allows the therapeut to optimize the management of patients with chronic sciatica. Some studies showed a reduction in both trunk and knee muscle strength in those patients, when compared with healthy subjects. Neurologic reason appears to be unlikely. This deficit may possibly be explained by muscle atrophy secondary to immobilization imposed by chronic pain. Therefore, the therapeutic program should control the pain but also strengthen both the trunk and lower extremity muscles. Some authors say that muscle atrophy mainly affects selective type II muscle fiber, which leads us to propose a strengthening at different contraction speeds especially the faster one (180°/s) to ensure a successful recovery [1] .

Evaluation of Isokinetic Trunk Muscle Strength in Adolescents With Normal and Abnormal Postures

ObjectiveThe aim of this study was to assess existing differences in the isokinetic trunk muscle strength in males and females aged between 10 and 11 years depending on body posture. MethodsThe study included 145 children (67 males and 78 females) divided into 2 age groups: 10-year-old males (x¯ = 9.98 ± 2.34 years) and females (x¯ = 9.85 ± 2.94 years) and 11-year-old males (x¯ = 11.14 ± 2.22 years) and females (x¯ = 11.15 ± 2.32 years). Posture in the sagittal plane was assessed by photogrammetry using the moiré projection technique. Based on a classification system, the participants were divided into subgroups of males and females with normal and abnormal postures. Trunk muscle strength was measured using isokinetic dynamometry. ResultsA high prevalence of abnormal posture in children aged between 10 and 11 years was observed, primarily represented by an excessive curvature of the spine in the sagittal plane. The males and females with poor posture recorded lower values in isokinetic trunk muscle strength. ConclusionThe results of the study point to the need for the application of suitable physiotherapy treatment (corrective measures/exercises) to treat musculoskeletal disorders to compensate for the loss of trunk flexor muscle strength in children with improper posture.

Isokinetic Training For Adolescents Low Back Pain Rehabilitation

Nespecifinės kilmės apatinės nugaros dalies skausmas išlieka didele šiuolaikinės visuomenės problema, o jį patiriančiųjų amžius vis jaunėja. Mokslininkai diskutuoja dėl skirtingų metodikų nevienodo efektyvumo skirtingo amžiaus pacientams. Liemens raumenų izokinetinio treniravimo terapinis poveikis esant apatinės nugaros dalies skausmams pradėtas tyrinėti visai neseniai. Mokslinių darbų, kuriuose nagrinėjama ši tematika, publikuota vienetai, o darbuose aprašomi tyrimai buvo atliekami tik suaugusiųjų populiacijose. Dėl to būtina ieškoti naujų veiksmingų nugaros skausmo gydymo metodikų (ypač vaikams), objektyviais tyrimo būdais patikrinti metodų efektyvumą. Tyrimo tikslas: palyginti izokinetinės treniruotės ir stuburo stabilizavimo pratimų efektyvumą gydant paauglių apatinės nugaros dalies skausmus. Tyrimo metodai. Tyrimas atliktas VšĮ VULSK filialo Vaikų ligoninėje, Vaikų fizinės medicinos ir reabilitacijos skyriuje. 2013.01 – 2014.06 mėn. dalyvavo pacientai, atlikę ambulatorinę reabilitaciją II, atitinkantys atrankos kriterijus. Tyrime dalyvavo 75 tiriamieji: 48 (64%) mergaitės ir 27 (36%) berniukai, nugaros skausmą patiriantys 12-17 m. amžiaus paaugliai. Tiriamųjų amžiaus vidurkis buvo 15,1±1,26m. Tiriamieji buvo suskirstyti į dvi grupes taikant atsitiktinės atrankos metodą. Abiejų grupių pacientams 16 dienų buvo taikoma po vieną 30 min. trukmės individualų kineziterapijos užsiėmimą (izokinetinė liemens raumenų treniruotė arba stuburą stabilizuojančių pratimų kompleksas). Kitas reabilitacines priemones grupės gavo vienodai, remiantis Lietuvos respublikos sveikatos apsaugos ministro V-50 įsakymu. Visi tiriamieji buvo vertinami parinktais ištyrimo metodais: matuojamas tiriamųjų ūgis ir svoris, vertinama juosmens raumenų statinė ištvermė pagal McGill metodiką, matuojamas juosmeninės stuburo dalies paslankumas pagal modifikuotą Clarkson metodiką. Izokinetiniu dinamometru „BIODEX 4 PRO“ buvo vertinama pilvo ir nugaros raumenų jėga ir dinaminė ištvermė. Tiriamųjų juntamo skausmo intensyvumas buvo vertinamas vizualinės analogijos skausmo skale. Roland-Morris klausimynas vertinant skausmo sukeltos negalios lygį. Ištyrimas buvo atliekamas prieš reabilitacijos ciklą, po jo. Statistinė duomenų analizė buvo atlikta naudojant specializuotus statistikos paketus. Po reabilitacijos abiejose tiriamųjų grupėse buvo nustatytas statistiškai reikšmingas juosmeninės stuburo dalies paslankumo padidėjimas (p&amp;lt;0,05), liemens raumenų statinės ištvermės padidėjimas (p&amp;lt;0,05), liemens tiesėjų dinaminės ištvermės bei maksimalios jėgos (p&amp;lt;0,05) padidėjimas. Abiejose grupėse buvo nustatytas statistiškai reikšmingas (p&amp;lt;0,05) funkcinio savarankiškumo lygio padidėjimas bei juntamo skausmo intensyvumo sumažėjimas (p&amp;lt;0,05). Lyginant abi grupes tarpusavyje nebuvo nustatyta reikšmingų skirtumų (p&gt;0,05), išskyrus - izokinetinė treniruotė geriau didina liemens statinę ištvermę (p&amp;lt;0,05). Išvados. Po reabilitacijos procedūrų ciklo tiriamųjų funkciniai rodikliai ryškiai pagerėjo, padidėjo savarankiškumo lygis. Nei viena metodika nebuvo efektyvesnė kitos atžvilgiu: vienodai gerai mažina skausmą bei jo sukeltus apribojimus ir negalią, vienodai gerai didina lankstumą bei juosmens paslankumo rodiklius, vienodai gerai didina liemens raumenų jėgą. Izokinetinė treniruotė geriau didina liemens statinę ištvermę.

Is there a relationship between core stability, balance and strength in amputee soccer players? A pilot study

The body is a kinetic chain and all the systems and muscle groups play important roles in this chain. Core stability, strength and balance are important components of performance within many sports, and in particular soccer. However, the relationship between these components is not fully understood. To investigate the relationship between core stability, balance and strength in amputee soccer players. Clinical pilot trial. Eleven amputee soccer players (mean age = 24.63 ± 6.48 years) participated in our study. A Kinesthetic Ability Trainer device was used to assess balance. Trunk strength was evaluated by isokinetic dynamometer. Gillet test was used to evaluate the sacroiliac joint movement. Modified plank test was used to determined dynamic core stability. Disability was evaluated using the Oswestry Disability Index. The results showed that there was a correlation between flexor isokinetic trunk muscle strength at the velocity of 60°/sec and modified plank test (r = 0.630, p = 0.038). There was a negative correlation between flexor isokinetic trunk muscle strength at the velocity of 180°/sec and Oswestry Disability Index score (r = -0.649, p = 0.031). Amputee soccer is a sport which is generally performed with one limb balance with crutches. It is therefore perceived that a relationship between balance and sacroiliac mobility, and should be considered for evaluation process and performance analysis in amputee soccer. However, in future studies, we recommend that such evaluations on amputee soccer players should be carried out with increased numbers.

A study of isokinetic trunk and knee muscle strength in patients with chronic sciatica

Objective To evaluate trunk and knee muscle strength in patients with chronic sciatica. Patients and method Twenty-eight patients with right-side chronic sciatica (group 1, G1) and 40 healthy controls (group 2, G2) were evaluated using an isokinetic dynamometer (Cybex Norm II). Quadriceps and hamstring muscle strength were evaluated at concentric velocities of 60 and 120°/s and the trunk muscles were evaluated at concentric velocities of 60 and 90°/s. Results G1 comprised 15 women and 13 men (mean ± SD age: 34.787 ± 6.06; weight: 65.85 ± 5.33 kg; height: 165 ± 6.92 cm). G2 comprised 20 women and 20 men (mean ± SD age: 35.92 ± 6.66; weight: 67.07 ± 6.12 kg; height: 165.82 ± 7.65 cm. There were no significant inter-group differences concerning these parameters. In G1, the peak torque values for the trunk extensors were 123.71 ± 32.45 and 108.85 ± 32.07 Newton metres (Nm) at angular velocities of 60 and 90°/s, respectively. In G2, the values were 192.73 ± 64.24 and 168.65 ± 53.96 Nm, respectively. In G1, the peak torque values for the trunk flexors were 134.32 ± 30.77 and 124.39 ± 32.59 Nm at angular velocities of 60 and 90°/s, respectively. In G2, they were 177.44 ± 44.1 and 157.81 ± 39.01 Nm, respectively. The difference between G1 and G2 was statistically significant. The peak torque for the right quadriceps in G1 was 100.03 ± 24.45 and 78.71 ± 22.92 Nm at angular velocities of 60 and 120°/s, respectively. In G2, these values were 160.5 ± 36.34 and 131.05 ± 33.42 Nm. The peak torque for the hamstrings in G1 was 56.42 ± 13.02 and 50 ± 13.55 Nm at angular velocities of 60 and 120°/s, respectively. In G2, these values were 97.77 ± 33.32 and 84.72 ± 31.41 Nm. Again the difference between G1 and G2 was statistically significant. We also noted a statistically significant difference between G1 and G2 in terms of the peak quadriceps and hamstring torque values on the left side. In G1, the quadriceps and hamstrings were significantly weaker on the sciatica side than on the unaffected side. Conclusion The present study demonstrated trunk and knee muscle weakness in patients with chronic sciatica, when compared with healthy subjects. This weakness was predominant on the sciatica side. Consequently, the management of these patients should include a knee muscle reinforcement programme.

Isokinetic trunk muscle strength of male judo athletes: Change in muscle contraction force accompanying change in angle velocity

Isokinetic trunk muscle strength of male judo athletes: Change in muscle contraction force accompanying change in angle velocity

Predictors of Change in Trunk Muscle Strength for Patients with Chronic Low Back Pain Randomized to Lumbar Fusion or Cognitive Intervention and Exercises

We have previously reported in two randomized controlled trials that cognitive intervention and exercises more effectively improved isokinetic trunk muscle strength than lumbar fusion and postoperative rehabilitation in patients with chronic low back pain. The aim of the present study was to predict changes in muscle strength as regard to changes in pain, function, fear-avoidance beliefs (self-rated questionnaires), changes in cross-sectional area and density of the back muscles and treatment. We assessed 1) isokinetic trunk muscle strength; 2) cross-sectional area and density of back muscles by computer-tomography (CT); and 3) pain, function, fear-avoidance beliefs, and self- efficacy for pain in the included patients at baseline and 1-year follow-up. Multiple regression analysis was performed with change in muscle strength as dependent variables, and changes in area/density and self-rated symptoms and treatment as independent variables. The correlations between the change in muscle strength and change in both cross-sectional area and density were weak (r < 0.1) and nonsignificant and these variables were not included in the multiple regression analysis. The change in pain, change in fear-avoidance beliefs, change in self-efficacy for pain and treatment explained 46% of the change in muscle strength, with change in pain and treatment as significant predictors. Our results emphasize the central role of pain and treatment for the improvements in muscle strength in patients with chronic low back pain.

Trunk muscle strength and disability level of low back pain in collegiate wrestlers.

Low back pain (LBP) is a frequent injury in athletes. This study examined the relationship between isokinetic trunk muscle strength and the functional disability level of chronic LBP. We particularly focused on the existence of radiological abnormalities (RA) in the lumbar region. Subjects were 53 collegiate wrestlers. Trunk extensor and flexor muscle strength was measured at three angular velocities (60, 90, and 120degrees x s(-1)). The examined parameters for trunk muscle strength were peak torque, work, average torque, and average power. The disability level of LBP was estimated by using two questionnaires. Based on the RA evaluation with x-ray and MRI, all 53 wrestlers were assigned to two groups as the RA group (N = 35, 66%) and the non-RA group (N = 18, 34%). Correlations between trunk muscle strength and the disability level of LBP in each group were analyzed with Spearman's rank test. Without considering the disability level, there were 14 subjects with LBP (40%) in the RA group and 8 (44%) in the non-RA. Significantly correlated parameters with the disability level of LBP could be observed only when the subjects were restricted to the non-RA group. The correlated parameters with the two questionnaires were peak torque at 120degrees x s(-1), work at 60degrees x s(-1) and 90degrees x s(-1), and average torque at 90degrees x s(-1) and 120degrees x s(-1). There were no significantly correlated parameters in the RA group. None of the trunk flexor parameters were significantly correlated with the disability level of LBP. The relatively low strength of trunk extensors may be one of the factors related to nonspecific chronic low back pain in collegiate wrestlers.

Trunk muscular strength in pre-pubertal children with and without back pain.

While in adulthood there is no proven relationship between back pain and trunk muscle strength, in pre-pubertal subjects this topic has been poorly studied. The aim of the study was to evaluate isometric and isokinetic trunk muscle strength in children with or without previous back pain. The recent occurrence of back pain (last 6 months) among 144 children (77 males, 67 females, age 11.9 +/- 0.3 years) was assessed using a questionnaire. Extensor and flexor trunk muscle strength was measured through isometric and isokinetic (60, 90, 120 degrees/s) tests. Peak torque (PT), PT angle, PT flexor/PT extensor ratio and intra-session coefficient of variation (COV) were determined. Flexor and extensor muscle PT, but not PT angle, were significantly higher in males than in females, irrespective of back pain occurrence. PT flexor/PT extensor ratio at 90 degrees angular velocities increased significantly only in males with back pain, compared with males without back pain. The COV trend was similar for flexor and extensor muscles. Isometric and isokinetic trunk muscle strength probably play a minor role in back pain occurrence in children. The isokinetic testing velocity may be important in determining trunk strength differences between children with and without back pain.

Assessment of isokinetic muscle strength in women who are obese.

Cross-sectional study of isokinetic trunk and knee muscle strength in women who are obese. To provide reference values, to identify variables that affect peripheral muscle strength, and to provide recommendations for isokinetic testing of trunk and knee muscles in women who are obese and morbidly obese. The assessment of peripheral muscle strength is useful for the quantification of possible loss of strength, for exercise prescription, and for the evaluation of the effect of training programs in obese individuals. Isokinetic trunk and leg muscle strength was assessed in 241 women who were obese (18-65 years, body mass index (BMI) > or = 30 kg/m2). Trunk flexion and extension peak torque (PT) was measured using the Cybex TEF dynamometer; trunk rotation (TR) PT was measured using the Cybex TORSO dynamometer; and knee flexion/extension (KFE) PT was measured using the Cybex 350 dynamometer. Body composition was assessed using the bioelectrical impedance method; physical activity was assessed using the Baecke questionnaire; and peak VO2 was assessed using an incremental exercise capacity test on a bicycle ergometer. To identify variables related to muscle strength, Pearson correlations were computed and a stepwise multiple regression analysis was performed. Pearson correlation coefficients of all strength measurements at 60 degrees/s revealed low-to-moderate negative associations with age and positive associations with mass, height, fat free mass (FFM), and peak VO2 (P < 0.05), except for gravity-uncorrected trunk extension strength, which was not related to mass. The sports index of the Baecke questionnaire was associated with TR PT (r = 0.20, P < 0.01) and KFE PT (r = 0.18, P < 0.05). The weight of the trunk accounts largely for the measured trunk extensor and flexor strength in women who are obese. Contributing variables of isokinetic trunk flexion and extension strength in women who are obese are age, height, and FFM; whereas sports activities and aerobic fitness are contributing factors for trunk rotational and knee extension strength. Recommendations for measuring isokinetic muscle strength in individuals who are obese are provided.

Reliability of isokinetic trunk muscle strength measurement.

To determine the intrarater and interrater reliability of reciprocal concentric trunk flexion and extension peak torque values at different angular velocities using the Cybex NORM isokinetic dynamometer. Trunk flexor and extensor muscles of 15 healthy subjects were assessed at 60 degrees/sec and 90 degrees/sec angular velocities. Each subject was tested by two physicians three times, with at least 48 hr between test sessions. Intraclass correlation coefficients were used to determine the intrarater and interrater reliability of the reciprocal concentric trunk flexion and extension peak torques at 60 degrees/sec and 90 degrees/sec angular velocities. For intrarater reliability intraclass correlation coefficients for trunk flexion, peak torque values ranged from 0.89 to 0.95; for the extensors, values ranged from 0.80 to 0.92. The intraclass correlation coefficient values for interrater reliability were also found to be highly reliable, and peak torque values demonstrated intraclass correlation coefficients values that ranged from 0.95 to 0.98. Reciprocal concentric trunk flexion and extension peak torque measurements at 60 degrees/sec and 90 degrees/sec angular velocities had a high intrarater and interrater reliability with the Cybex NORM isokinetic dynamometer in healthy subjects.