Airi Oksanen

Spinal mobility and trunk muscle strength in 15-year-old schoolchildren with and without low-back pain

From a population of 1,503 schoolchildren, 38 15-year-old children suffering from low-back pain and 38 asymptomatic controls were selected for testing of spinal mobility and trunk muscle strength. The asymptomatic controls were matched by age, sex, and school class. In the group with recurrent or continual low-back pain (17 boys and 21 girls), the boys were over 4 cm taller than those in the control group. In both sexes sagittal mobility was decreased in lumbar extension and straight leg raising, and increased in lumbar flexion. Endurance strength in the abdominal and back muscles was decreased compared to the control pupils, who reported no back pain at all in the questionnaire collected 1 year before the testing procedure. The pupils reporting sciatica (n = 7) at some time, in addition to recurrent low-back pain, had decreased lumbar flexion and side bending compared to those with recurrent low-back pain (n = 31) without sciatica. The results of the study indicated that in this growing-age population there was a subgroup with recurrent low-back pain having a different spinal mobility pattern as well as decreased trunk muscle strength.

Subject characteristics and low back pain in young athletes and nonathletes

Factors associated with low back pain (LBP) were sought by means of a questionnaire and physical measurements in 138 adolescents. One-hundred athletes and 38 nonathletes, 138 subjects total (58 boys and 80 girls; age range 10.3-13.3 yr), were studied. The questionnaire included questions on physical activity and LBP. Quantitative measurements on anthropometry, flexibility (joint hypermobility and muscular tightness), and strength were performed. There was no significant difference in the occurrence of LBP between athletes and nonathletes. Among the athletes, the duration of training during the past 12 months (min.wk-1) was higher in subjects with the experience of LBP during the past 12 months (N = 23) compared with nonsymptomatic subjects (N = 76) (mean 493 +/- 308 min.wk-1 vs 354 +/- 160 min.wk-1; P less than 0.0001). Similar differences were also seen between subjects with positive lifetime histories of LBP and nonsymptomatic subjects. Various differences were seen in the measurements of anthropometry, flexibility, and strength between boys and girls as well as between athletes and nonathletes. In a multivariate analysis, the cumulative incidence of lifetime history of LBP was associated with tightness of hip flexor muscles only (P = 0.014). LBP during the past 12 months was associated only with the amount of training during the past 12 months (min.wk-1) (P = 0.0066). Our study suggests that high training duration predisposes young athletes to LBP. However, e.g., the flexibility measurements cannot be used to determine athletes at high risk.

Lumbar Mobility and Low Back Pain During Adolescence A Longitudinal Three-Year Follow-up Study in Athletes and Controls

In this 3-year longitudinal study, we studied lumbar mobility and the occurrence of low back pain among 98 adolescents who were free of previous severe low back pain: 33 nonathletes (16 boys, 17 girls), 34 boy athletes (ice hockey and soccer players) and 31 girl athletes (figure skaters and gymnasts). During the fol lowup, low back pain lasting longer than 1 week was reported by 29 athletes (15 boys and 14 girls) and by 6 nonathletes (3 boys and 3 girls). In multivariate analy ses, participation in sports and low maximal lumbar flexion at the baseline predicted low back pain during the followup among boys; however, these factors ac counted for only 16% of the variability between the groups with and without low back pain. Among girls, decreased range of motion in the lower lumbar seg ments, low maximal lumbar extension, and high body weight at the baseline were predictive of low back pain during the followup, accounting for 31 % of the variabil ity between the groups. The girls in the lowest tertile of maximal lumbar extension at baseline had a relative risk of 3.4 to have future low back pain compared with those in the highest tertile. We conclude that the low individual physiologic maximum of lower segment lum bar extension mobility may cause overloading of the low back among athletes involved in sports with fre quent maximal lumbar extension and that it predicts future low back pain.

Muscle blood flow and flow heterogeneity during exercise studied with positron emission tomography in humans

Abstract Blood flow is the main regulator of skeletal muscles oxygen supply, and several studies have shown heterogeneous blood flow among and within muscles. However, it remains unclear whether exercise changes the heterogeneity of flow in exercising human skeletal muscle. Muscle blood flow and spatial flow heterogeneity were measured simultaneously in exercising and in the contralateral resting quadriceps femoris (QF) muscle in eight healthy men using H152O and positron emission tomography. The relative dispersion (standard deviation/mean) of blood flow was calculated as an index of spatial flow heterogeneity. Average muscle blood flow in QF was 29 (10) ml · (kg muscle)−1 · min−1 at rest and 146 (54) ml · (kg muscle)−1 · min−1 during exercise (P=0.008 for the difference). Blood flow was significantly (P < 0.001) higher in the vastus medialis and the vastus intermedius than in the vastus lateralis and the rectus femoris, both in the resting and the exercising legs. Flow was more homogeneous in the exercising vastus medialis and more heterogeneous (P < 0.001) in the exercising vastus lateralis (P=0.01) than in the resting contralateral muscle. Flow was more homogeneous (P < 0.001) in those exercising muscles in which flow was highest (vastus intermedius and vastus medialis) as compared to muscles with the lowest flow (vastus lateralis and the rectus femoris). These data demonstrate that muscle blood flow varies among different muscles in humans both at rest and during exercise. Muscle perfusion is spatially heterogeneous at rest and during exercise, but responses to exercise are different depending on the muscle.

Back extensor and psoas muscle cross-sectional area, prior physical training, and trunk muscle strength : a longitudinal study in adolescent girls

Abstract The association between physical training, low back extensor (erector spinae plus multifidus muscles) and psoas muscle cross-sectional areas (CSA) and strength characteristics of trunk extension and flexion were studied in adolescent girls. A group of athletes (n=49) (age range 13.7–16.3 years) consisting of gymnasts, figure skaters and ballet dancers was age-matched with non-athletes (n=17) who acted as a sedentary control group. The CSA of psoas muscles and multifidus plus erector spinae muscles were measured from lumbar axial images by magnetic resonance imaging. Maximal trunk extension and flexion forces were measured in a standing position using a dynamometer and trunk musculature endurance was evaluated using static holding tests. When CSA were adjusted with body mass, the athletes showed significantly greater CSA in both muscles studied (psoas P < 0.001; erector spinae plus multifidus P < 0.05) than the non-athletes. The athletes also had a greater absolute psoas muscle CSA (P < 0.01) and trunk flexion force (P < 0.01) compared to the controls. When the forces were expressed relative to body mass, the athletes were superior both in trunk flexion (P < 0.001) and extension (P < 0.001). There was a significant correlation between muscle CSA and strength parameters, but the force per muscle CSA did not differ significantly between the athletes and the non-athletes. In addition, the athletes showed a better body mass adjusted muscle endurance in trunk flexion (P < 0.05) than the non-athletes. Our study indicated that regular physical training enhances trunk musculature hypertrophy, force and endurance in adolescent girls, and that there is an association between muscle CSA and strength parameters.

Force production and EMG activity of neck muscles in adolescent headache.

Purpose. This study compared the maximal force, EMG/force ratio and co-activation characteristics of the neck-shoulder muscles between 30 adolescents with migraine-type headache, 29 with tension-type headache, and 30 headache-free controls. Method. Force was measured with surface electromyography (EMG) from the cervical erector spinae (CES), the sternocleidomastoid (SCM) and trapezius muscles during the maximal isometric neck flexion, neck extension and shoulder flexion. Results. Girls with migraine-type headache had higher EMG/force ratios between the EMG of the left agonist SCM muscle and the corresponding maximal neck flexion (p = 0.030) and neck rotation force to the right side (p = 0.024) than the girls with tension-type headache. Migrainous girls had more co-activation of right antagonist CES muscle during maximal neck flexion force than the girls without headache (p = 0.015). Neck force production showed no significant differences between girls. Girls with tension-type headache displayed lower left shoulder flexion force than girls with migraine-type headache (p = 0.005) or with no headache (p = 0.005). In boys, no significant differences were observed. Conclusions. Girls with tension-type headache and migraine-type headache have differences in neuromuscular function in the neck-shoulder muscles. The data amplify our knowledge of the neck-shoulder muscle dysfunction in adolescent headache, and may encourage the use of specific rehabilitation methods in the management of different types of headache.

Neck flexor muscle fatigue in adolescents with headache – An electromyographic study

Background: Muscular disorders of the neck region may be of importance for the etiology of tension‐type headache. However, in adolescents, there are no data on the association between neck muscle fatigue and headache.

Neck muscles cross‐sectional area in adolescents with and without headache – MRI study

Background: Cervical musculature may play an important role in the genesis of tension‐type headache. However, there are no reports on a possible association between the morphometrical features of the neck flexion and extension muscles and adolescence headache.

Training does not increase maximal lumbar extension in healthy adolescents.

OBJECTIVE: To investigate if there is training reserve in the maximal lumbar extension. DESIGN: Three-year longitudinal study. BACKGROUND: Among adults there is variation in the normal range of sagittal motion of the lumbar spine, but reduced spinal flexibility does not predict future occupational back pain. In various sports and in ballet, maximal extension of lumbar spine is a common manoeuvre, and low-back pain is also common. It is not known whether training increases maximal extension of healthy back. Forceful training of maximal extension may injure the anatomical structures limiting the extension range. METHODS: We compared lumbar sagittal flexibility to hip flexor and hamstring flexibility in a 3-year longitudinal study on female ballet dancers (n = 18), athletes (n = 31), and controls (n = 17) before and after their adolescent growth spurt. RESULTS: Ballet dancers had more flexible hamstrings and hip flexors than controls, but there were no group differences regarding the maximal lumbar flexion or extension. These results persisted throughout follow-up. CONCLUSIONS: The maximal physiological extension of the lumbar spine cannot be increased by training in healthy adolescents. RELEVANCE: An attempt to exceed the physiological maximum extension may only cause overly hard strain on specific anatomical structures of the lumbar spine. This knowledge should be considered when the rules of sports and choreography of dance performances are considered.

Trends of weekly musculoskeletal pain from 2000 to 2012: National study of Finnish university students

There are no nationwide trend surveys of the prevalence of musculoskeletal symptoms among university students. The aim of the study was to examine whether the prevalence of perceived musculoskeletal pain symptoms among Finnish university students has changed from 2000 to 2012, and to explore the co‐occurrence of these symptoms.