Trunk Strength Testing Research Articles

Reliability of trunk strength measurements with an isokinetic dynamometer in non-specific low back pain patients: A systematic review.

Imbalance or decreased trunk strength has been associated with non-specific low back pain (NSLBP). This systematic review aimed (I) to evaluate the quality of evidence of studies evaluating the reliability of trunk strength assessment with an isokinetic dynamometer in NSLBP patients, (II) to examine the reliability of trunk strength assessment using an isokinetic dynamometer in NSLBP patients and (III) to determine the most reliable protocol for trunk strength assessment in NSLBP patients. PRISMA guidelines were followed. Three databases were used: PubMed, Scopus, and Web of Science with the following keywords: Isokinetic, Dynamometer, Trunk strength testing, Muscle testing, Isokinetic measurement, CORE, Abdominal muscles, Abdominal wall, Torso, Trunk, Spine, Reliability and, Reproducibility. We included only test-retest studies, focused on the reliability of isometric and isokinetic strength assessed with an isokinetic dynamometer in NSLBP adults' patients, published in English and from inception to March 30, 2021. The methodological quality was evaluated with the CAT scale and QAREL checklist. Five hundred and seventy-seven articles were retrieved, of which five are included in this review. Three articles provide good quality of evidence, the reliability of trunk strength assessment in NSLBP patients is excellent, and the most reliable protocol for isometric assessment is in a seated position (ICC = 0.94-0.98) and for isokinetic strength in standing position, at 60∘/s and 120∘/s (ICC = 0.98). There is good quality evidence regarding the trunk strength assessment's reliability. Reliability is excellent in NSLBP patients; however, a familiarization process should be considered to obtain clinically reliable data. The most reliable protocol is in a seated position for isometric strength and a standing position for isokinetic strength.

Effect of Six-Week Resistance and Sensorimotor Training on Trunk Strength and Stability in Elite Adolescent Athletes: A Randomized Controlled Pilot Trial.

Intervention in the form of core-specific stability exercises is evident to improve trunk stability. The purpose was to assess the effect of an additional 6 weeks sensorimotor or resistance training on maximum isokinetic trunk strength and response to sudden dynamic trunk loading (STL) in highly trained adolescent athletes. The study was conducted as a single-blind, 3-armed randomized controlled trial. Twenty-four adolescent athletes (14f/10 m, 16 ± 1 yrs.;178 ± 10 cm; 67 ± 11 kg; training sessions/week 15 ± 5; training h/week 22 ± 8) were randomized into resistance training (RT; n = 7), sensorimotor training (SMT; n = 10), and control group (CG; n = 7). Athletes were instructed to perform standardized, center-based training for 6 weeks, two times per week, with a duration of 1 h each session. SMT consisted of four different core-specific sensorimotor exercises using instable surfaces. RT consisted of four trunk strength exercises using strength training machines, as well as an isokinetic dynamometer. All participants in the CG received an unspecific heart frequency controlled, ergometer-based endurance training (50 min at max. heart frequency of 130HF). For each athlete, each training session was documented in an individual training diary (e.g., level of SMT exercise; 1RM for strength exercise, pain). At baseline (M1) and after 6 weeks of intervention (M2), participants’ maximum strength in trunk rotation (ROM:63°) and flexion/extension (ROM:55°) was tested on an isokinetic dynamometer (concentric/eccentric 30°/s). STL was assessed in eccentric (30°/s) mode with additional dynamometer-induced perturbation as a marker of core stability. Peak torque [Nm] was calculated as the main outcome. The primary outcome measurements (trunk rotation/extension peak torque: con, ecc, STL) were statistically analyzed by means of the two-factor repeated measures analysis of variance (α = 0.05). Out of 12 possible sessions, athletes participated between 8 and 9 sessions (SMT: 9 ± 3; RT: 8 ± 3; CG: 8 ± 4). Regarding main outcomes of trunk performance, experimental groups showed no significant pre–post difference for maximum trunk strength testing as well as for perturbation compensation (p > 0.05). It is concluded, that future interventions should exceed 6 weeks duration with at least 2 sessions per week to induce enhanced trunk strength or compensatory response to sudden, high-intensity trunk loading in already highly trained adolescent athletes, regardless of training regime.

Feasability of An Eccentric Isokinetic Protocol to Induce Trunk Muscle Damage: A Pilot Study.

Eccentric exercise is discussed as a treatment option for clinical populations, but specific responses in terms of muscle damage and systemic inflammation after repeated loading of large muscle groups have not been conclusively characterized. Therefore, this study tested the feasibility of an isokinetic protocol for repeated maximum eccentric loading of the trunk muscles. Nine asymptomatic participants (5 f/4 m; 34±6 yrs; 175±13 cm; 76±17 kg) performed three isokinetic 2-minute all-out trunk strength tests (1x concentric (CON), 2x eccentric (ECC1, ECC2), 2 weeks apart; flexion/extension, 60°/s, ROM 55°). Outcomes were peak torque, torque decline, total work, and indicators of muscle damage and inflammation (over 168 h). Statistics were done using the Friedman test (Dunn’s post-test). For ECC1 and ECC2, peak torque and total work were increased and torque decline reduced compared to CON. Repeated ECC bouts yielded unaltered torque and work outcomes. Muscle damage markers were highest after ECC1 (soreness 48 h, creatine kinase 72 h; p<0.05). Their overall responses (area under the curve) were abolished post-ECC2 compared to post-ECC1 (p<0.05). Interleukin-6 was higher post-ECC1 than CON, and attenuated post-ECC2 (p>0.05). Interleukin-10 and tumor necrosis factor-α were not detectable. All markers showed high inter-individual variability. The protocol was feasible to induce muscle damage indicators after exercising a large muscle group, but the pilot results indicated only weak systemic inflammatory responses in asymptomatic adults.

Factorial Structure of Trunk Motor Qualities and Their Association with Explosive Movement Performance in Young Footballers.

This study examined the factorial structure of trunk motor qualities and their associations with explosive muscular performance of football players. Ninety-one young male football players (age: 15–21 years; body height: 1.78 ± 0.07 m; body mass: 70.3 ± 7.5 kg) performed a series of tests: four standing and four seated isometric trunk strength tests, seven trunk power (medicine ball throwing) tests, four trunk endurance tests and four explosive movement performance tests. A principal component factor analysis (PCA) was used to determine the structure of trunk motor qualities, and correlational analyses were used to assess linear associations between trunk motor qualities and explosive performance. The PCA revealed four independent factors—trunk power, standing and seated isometric trunk strength, and trunk muscle endurance. Only trunk power had significant moderate, logically positive associations with sprint and vertical jump performance (common variance: 25–36%), while other associations between trunk motor factors and explosive movement performance were generally low to very low. These results indicate that trunk muscle functions of football players can be described with three independent motor qualities—trunk power, trunk strength and trunk muscle endurance, with only trunk power being moderately associated with players’ sprinting and jumping performance.

Test-Retest Reliability and Known-Groups Validity of Trunk Muscle Tests in People With Multiple Sclerosis: A Cross-Sectional, Case-Control Study.

Research on muscle performance testing reliability in people with multiple sclerosis (MS) has focused on limb performance while less is known about trunk strength and endurance. This work aims to 1) establish test-retest reliability of trunk flexion, lateral flexion, and extension strength tests, and plank, side bridge, and Biering-Sørensen endurance tests in people with MS and matched healthy controls (HCs); 2) analyze known-groups validity of these tests in people with MS and HCs; 3) to compare groups for side-to-side differences; and 4) to describe the relationships between trunk performance and functional mobility tests. Fifteen people with MS (median Expanded Disability Status Scale=3) and 15 HCs underwent 2 trunk isometric strength and endurance testing sessions. Mobility was evaluated by Timed Up-and-Go test. Intraclass correlation coefficient, SEM, and minimal detectable change (MDC) were calculated. Between-group differences in trunk performance were tested using the ttest for independent measures. Between-group differences in an asymmetry index were analyzed by independent ttest. Bivariate correlations between trunk tests and mobility were also examined. All trunk tests showed good-to-excellent relative reliability in both groups (intraclass correlation coefficient>0.71). Regarding absolute reliability, strength tests were associated with low intersession variability in both groups (MDC: MS, 11.23%-36.45%; HCs, 26.60%-31.98%). Conversely, endurance tests showed higher variability scores in people with MS (MDC: MS, 69.55%-116.50%; HCs, 29.57%-54.40%). People with MS displayed significantly lower trunk performance. Likewise, the asymmetry index showed significantly higher scores in people with MS for endurance assessment but not in strength tests. Significant correlations were detected in people with MS between Timed Up-and-Go and several trunk tests (r=0.63-0.70). SEM and MDC scores revealed similar consistency and variability between groups for strength tests, whereas higher variability was observed for endurance tests in people with MS. Trunk strength tests are reliable and present discriminant validity to distinguish mildly disabled people with MS from HCs. Conversely, the high measurement error and variability of the endurance tests may hinder their application in intervention programs. Determining the reliability and validity of the tests currently used to assess trunk function is of the greatest importance for people with MS (who show not only impaired trunk function but also wide fluctuations in performance), as it requires consistent and accurate measurements that are sensitive enough to detect minimal changes induced by rehabilitation.

Change of Direction Performance Is Influenced by Asymmetries in Jumping Ability and Hip and Trunk Strength in Elite Basketball Players

Change of direction (COD) ability is essential for sport performance in high level team sports such as basketball, however, the influence of asymmetries on COD ability is relatively unknown. Forty-three junior and senior level elite basketball players performed isometric hip and trunk strength testing, passive hip and trunk range of motion testing, and unilateral horizontal and vertical jumps, as well as the T-test to measure COD performance. Mean asymmetry values ranged from 0.76% for functional leg length up to 40.35% for rate of torque development during hip flexion. A six-variable regression model explained 48% (R2 = 0.48; p &lt; 0.001) of variation in COD performance. The model included left hip internal/external rotation strength ratio, and inter-limb asymmetries in hip abduction rate of torque development, hip flexion range of motion, functional leg length, single leg triple jump distance, and peak torque during trunk lateral flexion. Results suggest that the magnitude of asymmetries is dependent of task and parameter, and using universal asymmetry thresholds, such as &lt;10 %, is not optimal. The regression model showed the relationship between asymmetries and COD performance. None of tests were sufficient to explain a complex variable like COD performance.

High Intensity Training to Treat Chronic Nonspecific Low Back Pain: Effectiveness of Various Exercise Modes.

High-intensity training (HIT) improves rehabilitation outcomes such as functional disability and physical performance in several chronic disorders. Promising results were also found in chronic nonspecific low back pain (CNSLBP). However, the impact of different exercise modes on HIT effectiveness in CNSLBP remains unclear. Therefore, this study evaluated the effectiveness of various HIT exercise modes and compared differences between these modes, on pain intensity, disability, and physical performance, as a therapeutic intervention for persons with CNSLBP. In a randomized comparative trial, consisting of a 12-week program, persons with CNSLBP were divided into four HIT groups, i.e., cardiorespiratory interval training coupled with either general resistance training, core strength training, combined general resistance and core strength training, or mobility exercises. Before and after the program, the Numeric Pain Rating Scale (NPRS), Modified Oswestry Disability Index (MODI), and Patient Specific Functioning Scale (PSFS) were recorded, and a cardiopulmonary exercise test (VO2max, cycling time) and isometric trunk strength test (maximum muscle torque) were performed. Eighty participants (mean age: 44.0 y, 34 males) were included. Improvements were found within all groups after the HIT programs and ranged from −39 to −57% on the NPRS, +27 to +64% on the MODI, +38 to +89% on the PSFS, +7 to +14% on VO2max, and +11 to +18% on cycling time. No differences between groups were found. High-intensity cardiorespiratory interval training improves CNSLBP rehabilitation outcomes when performed with other HIT exercise modes or mobility exercises. Hence, when setting up an exercise therapy program in CNSLBP rehabilitation, various HIT modes can be considered as therapy modalities.

Prediction of competition performance via selected strength-power tests in junior weightlifters.

Previous studies were limited to physical measurements or included very few performance test batteries, which has hindered the determination of the best tests for predicting competition performance in weightlifters. This study aimed to examine the relationships between body composition, Wingate anaerobic power, vertical jump height, isokinetic strength, handgrip strength, trunk strength, and competition performance and to determine the best predictors of competition performance in male junior weightlifters. Sixty-seven male junior weightlifters (age 16.6±1.5 years, height 166.6±5.2 cm, body mass 67.0±9.3 kg) voluntarily participated in this study. After a national weightlifting competition, the participants were evaluated for anthropometric measurements, Wingate anaerobic power, isokinetic strength, vertical jump, handgrip strength, and trunk strength tests. The competition performance of the participants was calculated using the Sinclair equation and used as the dependent variable in statistical analysis. The correlations between the variables calculated from the five strength-power tests and the Sinclair score were significant (r=0.448 to 0.951, P≤0.05). The regression model suggested that the best predictors of weightlifting performance were Wingate mean power, the countermovement jump with arm swing, and body fat percentage, which accounted for approximately 88% of the common variance associated with competition performance in male junior weightlifters. The results of this study showed that the predictors of weightlifting performance were Wingate mean power, countermovement jump with arm swing, and body fat percentage.

Disability, kinesiophobia, perceived stress, and pain are not associated with trunk muscle strength or aerobic capacity in chronic nonspecific low back pain

ObjectivesTo investigate to which extent disability, psychological and pain-related factors are associated with the outcomes of an isometric trunk muscle strength test and a cardiopulmonary exercise test in persons with chronic nonspecific low back pain (CNSLBP). DesignCross-sectional study. SettingREVAL Rehabilitation Research Center (Hasselt, Belgium). ParticipantsPersons with CNSLBP. Main outcome measuresQuestionnaires concerning disability, patient specific functioning, kinesiophobia, perceived stress, pain intensity, and central sensitization were recorded. Outcomes of an isometric trunk strength test (maximum back and abdominal torque) and cardiopulmonary exercise test (VO2max) were assessed. Multivariate linear regression models determined factors explaining outcome variance. ResultsData of 101 persons (39 males, mean age: 44.2y (SD = 9.6)) was assessed. Neither disability, nor psychological, nor pain-related factors were associated with the assessments. Variance in back muscle strength (R2 = 0.44, F = p < 0.01), abdominal muscle strength (R2 = 0.68, F = p < 0.01), and aerobic capacity (R2 = 0.76, F = p < 0.01) could only be explained through the included demographics covariates (age, gender, weight). ConclusionThis study highlighted the lack of biopsychosocial factors in explaining variance in outcomes of abdominal and back strength, and aerobic capacity in persons with CNSLBP with characteristics as depicted in the current sample. This information supports the valid interpretation of the outcomes of these assessments.

Relationship between anaerobic power and isokinetic trunk strength in college male soccer players

Background: Although anaerobic power affects soccer performance, the relationship between anaerobic power and core strength in soccer players has not been well studied. The aim of our study was to investigate the relationship between anaerobic power and core strength. Methods: The subjects were 31 college male soccer players. Their physical characteristics, anaerobic power (Wingate anaerobic test: WAnT), and core strength (isokinetic trunk strength test; ITST) were measured. To describe the effect of core strength on anaerobic power, the Pearson correlation coefficient and multiple regression analysis were conducted. Results: A significant relationship between the WAnT peak power (PP) and variables of ITST was observed (vs. trunk extension strength; TES: r = 0.629, vs. trunk flexion strength; TES: r = 0.507, vs. trunk extension power; TEP: r = 0.411, and vs. trunk flexion power; TFP: r = 0.555). We also found a relationship between the WAnT mean power (MP) and variables of ITST (vs. TES: r = 0.654, vs. TFS: r = 0.559, vs. TEP: r = 0.468, and vs. TFP: r = 0.720). The variables of ITST affecting WAnT PP were TES (P &lt; 0.001) and TFP (P &lt; 0.001). The explanatory power of these variables was 59.7% (R2 = 0.597). The variables of ITST affecting WAnT MP were TFS (P &lt; 0.001) and TSE (P &lt; 0.001). The explanatory power of these variables was 72.7% (R2 = 0.727). Conclusion: The results of our study showed that isokinetic trunk strength significantly associated with the WAnT peak and mean power.

Back Pain in Adolescent Athletes: Results of a Biomechanical Screening.

The aim was to use a short biomechanical test battery to screen adolescent athletes with and without back pain to reveal relevant and possibly preventable deficits. 1 559 adolescent athletes (m/f 945/614; 13.2±1.6y) were included. Back pain was assessed (1–5: 1=no pain; 5=maximum pain) for dichotomous categorization into back pain (BP: pain>2, n=113), healthy (NBP All : pain=1, n=1 213) and matched healthy (NBP matched : pain=1, n=113) athletes. Athletes performed stability, performance (jumps) and trunk strength testing. The center of pressure displacement [mm], jump height [cm], peak force [N], contact time [ms] and peak torque of the trunk [Nm] were analyzed. Analysis showed a statistically significant influence of trunk strength on back pain (BP/NBP ALL ). Nevertheless, after including co-variables (anthropometrics, gender and training volume), there were no significant variables detectable any longer. ANOVA identified no group differences (BP/NBP matched ) in the outcome measurement for the biomechanical tests (p>0.05). This short biomechanical screening shows no sufficient differentiation in adolescent athletes for back pain. Therefore, age, training load and gender has greater relevance than strength deficits or postural control. This is challenging for further understanding of the complex conditions in young athletes with back pain.

Absolute and relative reliability of isokinetic and isometric trunk strength testing using the IsoMed-2000 dynamometer

ObjectivesThe present study aimed to assess the between day reliability of isokinetic and isometric peak torque (PT) during trunk measurement on an isokinetic device (IsoMed 2000). DesignTest-retest-protocol on five separate days. ParticipantsFifteen healthy sport students (8 female and 7 male) aged 21 to 26. Main Outcome MeasuresPT was assessed in isometric back extension and flexion as well as right and left rotation. Isokinetic strength was captured at a speed of 60°/s and 150°/s for all tasks. ResultsFor none of the assessed parameters a meaningful variation in PT during test days was observed. Relative reliability (ICC = 0.85–0.96) was excellent for all tasks. Estimates of absolute reliability as Coefficient of Variation (CoV) and Standard Error of Measurement (SEM in Nm/kg lean body mass) remained stable for isometric (6.9% < CoV < 9.4%; 0.15 < SEM < 0.23) and isokinetic mode (60°/s: 3.7% < CoV < 8.6%; 0.08 < SEM < 0.24; 150°/s: 6.9% < CoV < 12.4%; 0.10 < SEM < 0.31). In contrast, reliability between familiarization day and day 1 was lower (6.6% < CoV < 26.2%; 0.10 < SEM < 0.65). ConclusionsTrunk strength measurement in flexion and extension or trunk rotation in either isometric or isokinetic condition is highly reliable. Therefore, it seems possible to elucidate changes which are smaller than 10% due to intervention programs when a preceding familiarization condition was applied.

Muscle Activation and Performance During Trunk Strength Testing in High-Level Female and Male Football Players.

For performance and injury prevention in sport, core strength and endurance are focused prerequisites. Therefore we evaluated characteristics of trunk muscle activation and performance during strength-endurance related trunk field tests. Strength-endurance ability, as total time to failure, and activation of trunk muscles was measured in 39 football players of the highest German female football league (Bundesliga) (N = 18, age: 20.7 y [SD 4.4]) and the highest national male under-19 league (N = 21, age: 17.9 y [0.7]) in prone plank, side plank, and dorsal position. Maximal isometric force was assessed during trunk extension and flexion, rotation, and lateral flexion to normalize EMG and to compare with the results of strength-endurance tests. For all positions of endurance strength tests, a continuous increase in normalized EMG activation was observed (P < .001). Muscle activation of the rectus abdominis and external oblique in prone plank position exceeded the maximal voluntary isometric contraction activation, with a significantly higher activation in females (P = .02). We conclude, that in the applied strength-endurance testing, the activation of trunk muscles was high, especially in females. As high trunk muscle activation can infer fatigue, limb strength can limit performance in prone and side plank position, particularly during high trunk muscle activation.

Reproducibility of maximum isokinetic trunk strength testing in healthy adolescent athletes

BackgroundIn adolescents athletes isokinetic testing is applied to describe population specific characteristics in trunk strength. However, reproducibility of trunk tests used remains unclear. Aim of the study was to evaluate reproducibility of isokinetic trunk strength testing in adolescent athletes. MethodsTrunk strength was assessed twice in healthy adolescents (N=13; 15.9±1.7yrs; 1.73±0.10m; 69.0±17.0kg). Isometric, concentric and eccentric maximum strength measurements in rotation and flexion/extension were performed. Outcome measures were peak torque (PT; [Nm]), normalized peak torque (PTnorm; [Nm/kgBW]) and ratios of right/left rotation and flexion/extension. Intra class correlation coefficient (ICC), standard error of measurement (SEM), smallest real difference (SRD), Bland and Altman analysis (bias; 95%-limits of agreement (LoA)) and Test-Retest-Variability (TRV) were calculated. ResultsICC ranged between 0.65-0.90 in rotation and 0.69-0.94 in flexion/extension. Systematic error varied between -0.15 to 12.3% (rotation) and -7.0 to 8.8% (flexion and extension). TRV in rotation ranged between 14.6-21.3%. TRV in flexion/extension, except isometric extension, was below 15%. SEM/SRD ranged between 12.6/35.0% and 24.0/66.5% in rotation and 7.2/20.0% and 17.8/49.5% in flexion/extension. ConclusionsResults indicate acceptable reproducibility of isokinetic trunk strength measurements for adolescents in the planes tested. This pilot study indicates that maximum isokinetic trunk strength testing seems to be applicable in this special population, but needs further validation. Level of EvidenceLevel IV.

The effects of Zumba training on cardiovascular and neuromuscular function in female college students

The present study examined the effects of Zumba training (group fitness based on salsa and aerobics) on endurance, trunk strength, balance, flexibility, jumping performance and quality of life (QoL) in female college students. Thirty female participants were randomly assigned (strata: age, BMI and physical activity) to an intervention (INT, n = 15: age: 21.0 ± 2.3 years; BMI: 21.8 ± 3.0 kg/m2; physical activity (PA): 7.6 ± 4.6 h/week) or control group (CON, n = 14: age: 21.0 ± 2.8 years; BMI: 21.0 ± 2.1 kg/m2; PA: 7.3 ± 3.6 h/week). Instructed Zumba training was provided twice a week for 8 weeks (training attendance: 100%). QoL was assessed using the WHO-QoL-BREF questionnaire. Endurance was measured with the 6-min walking test (6MWT). Trunk flexibility was assessed with the stand-and-reach-test and lower-extremity strength with the jump-and-reach-test. The star excursion balance test (SEBT) was employed to assess dynamic balance. Trunk strength endurance was examined using the Swiss global trunk strength test in prone and lateral (left, right) positions. All testings were performed before and after the training period. We observed large statistically significant between-group effects of total QoL score (INT: +9.8%, CON: +0.4%, p < 0.001; partial eta squared ), 6MWT distance (INT: +21%, CON: −2%, p < 0.001, ), trunk strength endurance (prone, INT: +48%, CON: +11%, p = 0.04, ; lateral-left, INT: +71%, CON: +11%, p = 0.01, , lateral-right, INT: +54%, CON: +11%, p = 0.01, ) and dynamic balance (all eight reaching distances of the SEBT, INT: +11−26%, CON: +1.1−3.8%, 0.001 < p < 0.04, 0.14 < ) with significantly larger improvements for INT. Flexibility and jump performance were not relevantly affected (p > 0.05). Instructed Zumba training can be applied to improve well-being, aerobic fitness and neuromuscular function in female college students.

Physical Characteristics of Women With Severe Pelvic Girdle Pain After Pregnancy

Descriptive cohort study. This study aims to further elucidate the differences in physical characteristics of women with severe pregnancy-related pelvic girdle pain (PGP). There is increasing interest in pelvic girdle pain (PGP). To our knowledge, this is the first study on a large population of patients with severe PGP, after pregnancy, based on high cutoff scores on diagnostic PGP tests. Two hundred five patients were selected from the outpatient clinic of a rehabilitation center. Patients were divided in 3 inclusion groups based on the total number of positive scores on 5 diagnostic tests; i.e., active straight leg raise test, posterior pelvic pain provocation test, long dorsal sacroiliac ligament test, and hip abduction and adduction strength tests. These inclusion groups were related to the data on trunk strength test, general provocation tests, Quebec Back Pain Disability Scale (QBPDS) and activities of daily living. A typical pattern of PGP emerges from this study. The mean group score on the active straight leg raise, posterior pelvic pain provocation, and long dorsal sacroiliac ligament tests became higher when more than 3 inclusion tests were positive. Hip abduction and adduction strength became lower with more positive tests. The QBPDS score was overall high and significantly higher for 5 positive tests compared with 3 and 4 positive tests. This shows that the number of positive tests, the individual score on the diagnostic tests, and the QBPDS could all be an indicator for severity of PGP. Among the general pain provocation tests, both the passive hip flexion test and the upper and middle sacral thrust test scored high. The maximal isometric strength of trunk muscles was below the 10th percentile compared with women without complaints and was even less for 5 positive inclusion tests. It is confirmed that there is a typical order for difficulties with daily activities for PGP patients as follows (most difficult first): standing still, cycling, walking, sitting, and lying. The study shows that the level of severity in PGP can be adequately assessed by a combination of specific tests.

Health-related fitness in Swedish adolescents between 1987 and 2001

Aim: To assess trends in neuro-muscular and cardio-respiratory fitness and morphological fitness in Swedish adolescents between 1987 and 2001. Methods: Comparison of data from two samples, one from 1987 (n= 479) and one from 2001 (n = 1470). Subjects underwent functional tests of muscular strength in the lower limbs, trunk and upper body, sub-maximal ergometrics, and measurement of body mass and height. Results: Cardio-respiratory fitness showed only small changes between 1987 and 2001 among boys, with no changes in girls. Neuro-muscular fitness, as measured by three functional tests, was lower in 2001 compared to 1987. The most pronounced changes in these functional tests were found in the arm-hang test, while changes in lower body and trunk strength tests were less. Our results indicate that the difference in the prevalence of overweight in adolescents between 1987 and 2001 is mainly due to a large change in the most unfit group. The fittest group showed only marginal changes. Conclusion: We suggest that the differences in neuro-muscular fitness are at least partly due to differences in the amount and nature of physical activity, and that this might lead to consequences for health later in life.

Health‐related fitness in Swedish adolescents between 1987 and 2001

To assess trends in neuro-muscular and cardio-respiratory fitness and morphological fitness in Swedish adolescents between 1987 and 2001. Comparison of data from two samples, one from 1987 (n = 479) and one from 2001 (n = 1470). Subjects underwent functional tests of muscular strength in the lower limbs, trunk and upper body, sub-maximal ergometrics, and measurement of body mass and height. Cardio-respiratory fitness showed only small changes between 1987 and 2001 among boys, with no changes in girls. Neuro-muscular fitness, as measured by three functional tests, was lower in 2001 compared to 1987. The most pronounced changes in these functional tests were found in the arm-hang test, while changes in lower body and trunk strength tests were less. Our results indicate that the difference in the prevalence of overweight in adolescents between 1987 and 2001 is mainly due to a large change in the most unfit group. The fittest group showed only marginal changes. We suggest that the differences in neuro-muscular fitness are at least partly due to differences in the amount and nature of physical activity, and that this might lead to consequences for health later in life.

The Anthropometric Factor in Assessment of Physical Abilities of Young Female Volleyballers (Aged 13-16)

The study discusses the relations between the body build of 46 young female volleyballers (age 13-16 years, 51 characteristics including 11 skinfolds) and the results of nine physical ability tests. The tests included four jump tests, endurance, trunk strength, flexibility, speed and medicine ball throwing tests. Correlation of basic anthropometric characteristics with test results showed that all the tests except the trunk strength test and the flexibility test were to a greater or smaller extent related to body measurements. Body fat content had a negative impact on jump tests, and on endurance and speed tests. The endurance test correlated negatively with body measurements; smaller players had greater endurance. In regression analysis, to show the dependence of physical ability test results on body build, two models were used: 1) height, weight and age; 2) other anthropometric characteristics. The second model predicted the variability of tests results within 48-89%. In all cases the model of height, weight and age yielded somewhat less significant results. The test results were placed in a 5 SD classification of weight and height. The classification showed that jumping ability improved gradually from the small to the medium to the big class; leptomorphs could jump higher than pycnomorphs. In speed tests leptomorphs were more successful than pycnomorphs.

A predictive model for outcome after conservative decompression surgery for lumbar spinal stenosis.

This study was designed to develop predictive models for surgical outcome based on information available prior to lumbar stenosis surgery. Forty patients underwent decompressive laminarthrectomy. Preop and 1-year postop evaluation included Waddell's nonorganic signs, CT scan, Waddell disability index, Oswestry low back pain disability questionnaire, low back outcome score (LBOS), visual analog scale (VAS) for pain intensity, and trunk strength testing. Statistical comparisons of data used adjusted error rates within families of predictors. Mathematical models were developed to predict outcome success using stepwise logistic regression and decision-tree methodologies (chi-squared automatic interaction detection, or CHAID). Successful outcome was defined as improvement in at least three of four criteria: VAS, LBOS, and reductions in claudication and leg pain. Exact logistic regression analysis resulted in a three-predictor model. This model was more accurate in predicting unsuccessful outcome (negative predictive value 75.0%) than in successful outcome (positive predictive value 69.6%). A CHAID model correctly classified 90.1% of successful outcomes (positive predictive value 85.7%, negative predictive value 100%). The use of conservative surgical decompression for lumbar stenosis can be recommended, as it demonstrated a success rate similar to that of more invasive techniques. Given its physiologic and biomechanical advantages, it can be recommended as the surgical method of choice in this indication. Underlying subclinical vascular factors may be involved in the complaints of spinal stenosis patients. Those factors should be investigated more thoroughly, as they may account for some of the failures of surgical relief. The CHAID decision tree appears to be a novel and useful tool for predicting the results of spinal stenosis surgery