Objective: This study aimed to clarify the characteristics of the patients who had hip osteoarthritis (hip OA) of more than K-L grade 3 and did not need total hip replacement (THR) two years after the diagnosis.Methods: Twenty-four patients who were followed up for at least 2 years were included and classified into surgical and non-surgical groups depending on the need for THR. Pain (rest pain, motion pain, gait pain), hip range of motion, performance tests (time up and go test (TUG), 10 m gait speed, 2-step test, one-leg standing time, chair standing-5 (CS-5)), and Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire (JHEQ) were evaluated at the initial visit.Results: Rest pain was significantly lower in non-surgical group compared to surgical group (p<0.01). JHEQ pain score (p<0.01), motor score (p=0.03), and mental health score (p<0.01) were significantly higher in non-surgery group than those in surgery group.Conclusion: Even if you have end-stage hip OA, those with low rest pain and a high JHEQ score at the time of initial diagnosis may be able to live for two years without undergoing surgery. In patients with hip OA of more than K-L grade 3, low rest pain and a high JHEQ score at the initial visit were associated with avoiding THR for two years.

A study was conducted to clarify the effects of running intensity and duration of endurance training on myoglobin concentration ( [Mb] ) in rat skeletal muscles, and to clarify its temporal changes during the training. One hundred five male Wistar rats were divided into a training group and an untrained group. The training was carried out at 5 times a week for 12 weeks when the animals were 4 to 16 weeks of age. The training intensities were set at 20, 30 and 40 m/min with a duration of 60 min. The training duration was varied to 30, 60, 90 and 120 min when the rats were trained at 30 m/min. The temporal changes in the [Mb] were examined after the first, third and ninth week of training, during which the rats were trained at 40 m/min for 60 min per session. Three muscles (soleus: Sol, plantaris: P1, gastrocnemius-surface/deep: Gas-S, Gas-D) were analyzed for the [Mb] and citrate synthase activity (CS activity) . With regard to the intensity of training, the [Mb] increased with exercise intensity in Sol, Gas-D and P1, but not in Gas-S. P1 showed a greater increase of the [Mb] than Sol or Gas-D. On the other hand, CS activity in red muscle (Sol and Gas-D) increased even at low intensity, whereas white muscle (fast-twitch muscle: Pl and Gas-S) showed a significant increase in CS activity at an intensity of 40m/min. As to the duration of training, the [Mb] increased with the duration of running at 30 m/min of intensity, and showed the maximal adaptation with 90-min duration in all muscles except for Gas-S. Changes in CS activity according to the duration of running were similar to those for the [Mb] in all muscles. Finally, the [Mb] increased significantly with prolongation of the training period (after the 1 st, 3 rd and 9 th weeks training) in all muscles except Gas-S. However, the adaptive response of Mb tended to be delayed as compared with CS activity. These results suggest that 1) the response of Mb to training stimuli can depend on the muscle specificity (fiber type composition or the initial [Mb] ), and level of motor unit recruitment in usual, 2) Mb synthesis can be enhanced by an increase of training intensity, 3) a training duration of 90 min can bring out the Mb adaptation maximally and 4) the adaptive response of Mb would need more time as compared with CS activity.

The physiological cross-sectional area (PCSA) of knee extensors (KE) and flexors (KF) was determined using magnetic resonance imaging (MRI) in humans. Twenty two healthy male volunteers were assigned to the subjects and MRI was taken to obtained 41-52 consecutive axial images (slice thickness ; 10 mm, interslice gap ; 0 mm) from right-leg thigh. From these images, anatomical cross-sectional area (ACSA) of KE and KF was determined. Muscle volume was calculated from the summation of each ACSA and the distance between each section. Muscle length was determined as the distance from most proximal to most distal images in which the muscle visible. The PCSA of each muscle was calculated as muscle volume times the cosine of the angle of fiber pinnation divided by fiber length, where published fiber length : muscle length ratio were used to estimate fiber length. The isokinetic knee extension and flexion (angular velocity ; 30, 60, 180, 300, 450 deg/sec) was measured to estimate the muscle force at KE and KF. Specific tension of KE and KF was calculated muscle force deviled by PCSA. The mean muscle volume of KE and KF was 2178, 1141 cm³. The ratio of KE : KF was 2.6. The mean fiber length in KE was 7-8 cm, and in KF was 6-42 cm. Peak torque during knee extension was significantly higher than knee flexion at all angular velocities. The specific tension of KF was higher than that of KE at all tendon velocities. Moreover, relationships between specific tension and tendon velocity/fiber length, KF was still higher than that of KE. These results suggest that the capacity of tension development differ between KE and KF under the same shortening velocity per unit of sarcomere.

In this study, the effect of moderate endurance training on muscle morphological properties of human thigh muscles and isokinetic strength was examined. Five sedentary females carried out a training program of 30 min./day, 3 times a week for a ten-week period. The load requirement was set to 60% of maximal aerobic capacity (Vo₂max) of the subjects. In the determination of muscle cross-sectional areas (CSAs) by MRI, longitudinal sections were first imaged, and ten axial images along the length of femur were taken before and after the endurance training. Muscle CSA and mus-cle volume of knee extensors (KE), flexors (KF), and adductors (AD) were calculated, using the ten axial images. Vo₂max was significantly increased after endurance training (14.6%, p<0.01) . Muscle CSA in KE was significantly increased at the ten levels of femur length. There were also significant increases at seven levels of femur length after endurance training in KF (p<0.05, and 0.01) . Percentage increase of msucle CSA in KE and KF were 10.9 to 16.5% and 7.7 to 15.8%, respectively. Although the muscle volume of KE, KF, and AD was significantly increased, no change in fat volume was observed after endurance training. Isokinetic knee extension and flexion peak torque and peak torque per unit of muscle CSA at three angular velocities (30, 180, and 300 deg/sec) didn't show significant changes. These results suggest that muscle hypertrophy induced by moderate endurance training has no effect on muscle strength.

We examined the time course of soleus muscle fiber type composition. Soma area and succinate dehydrogenase (SDH) activity of soleus motoneurons during three weeks of hindlimb suspension (HS) in rats. Adult female Wistar rats (n=34, 252-288g BW) were divided into four groups: control (n=8), hindlimb suspended for one week (HS 1 wk, n=8), two weeks (HS 2 wk, n=9), and three weeks (HS 3 wk, n=9) . Soleus muscle fiber composition was calculated from transverse sections stained for myosin ATPase (preincubation pH 10.3, 4.3) . The fiber type composition did not change in the HS 1 wk, but in the HS 2 wk and HS 3 wk, the proportion of type I fibers decreased and that of type IIc and ha fibers increased. Using a fluorescent neuronal tracer nuclear yellow, motoneurons innervating the soleus muscle were identified, and the soma area and SDH activity were measured. The soma area did not change for up to two weeks of HS, but decreased in the HS 3 wk. Compared with control, SDH activity of soleus motoneurons decreased in the HS 1 wk. However, in the HS 2 wk, the activity increased to the level of control. In the HS 3 wk, the activity tended to increase further. Generally, muscle fibers and their motoneurons have unitary characteristics. However, these results suggest that change in soleus muscle fiber composition are not accompanied by changes in soma area and SDH activity in soleus motoneurons during three weeks of HS.

In this study, the effect of moderate endurance training on muscle morphological properties of human thigh muscles and isokinetic strength was examined. Five sedentary females carried out a training program of 30 min./day, 3 times a week for a ten-week period. The load requirement was set to 60% of maximal aerobic capacity (Vo₂max) of the subjects. In the determination of muscle cross-sectional areas (CSAs) by MRI, longitudinal sections were first imaged, and ten axial images along the length of femur were taken before and after the endurance training. Muscle CSA and mus-cle volume of knee extensors (KE), flexors (KF), and adductors (AD) were calculated, using the ten axial images. Vo₂max was significantly increased after endurance training (14.6%, p<0.01) . Muscle CSA in KE was significantly increased at the ten levels of femur length. There were also significant increases at seven levels of femur length after endurance training in KF (p<0.05, and 0.01) . Percentage increase of msucle CSA in KE and KF were 10.9 to 16.5% and 7.7 to 15.8%, respectively. Although the muscle volume of KE, KF, and AD was significantly increased, no change in fat volume was observed after endurance training. Isokinetic knee extension and flexion peak torque and peak torque per unit of muscle CSA at three angular velocities (30, 180, and 300 deg/sec) didn't show significant changes. These results suggest that muscle hypertrophy induced by moderate endurance training has no effect on muscle strength.

We investigated the muscle energetics using ³¹P nuclear magnetic resonance (³¹P NMR) spectroscopy, muscle cross-sectional area by magnetic resonance imaging (MRI), isokinetic strength, maximal anaerobic power and 40-sec maximal cycling test (40 seconds power) in All Japan soccer players (JPN: n=6), Olympic and Youth representatives (OL: n=6), and Japan Soccer League players (JSL: n=5) . There was no significant difference in muscle energy metabolism measured by ³¹P NMR between the JPN and the OL or JSL players at rest, during exercise, or in the recovery period. The total muscle cross-sectional area was significantly larger in the JPN players than in the OL players at the upper (70%) and the middle (50%) parts of the thigh (p<0.05) and than in the JSL players in the upper (p<0.01), middle (p< 0.05), and lower (30%) parts (p<0.01) . The isokinetic strength in left leg extension at 180 deg/sec was significantly greater in the JPN players than in the OL players (p<0.05) . Muscle strength was also greater in extension of both legs at 450 deg/sec (left p<0.05, right p<0.01) in the JPN players than in the JSL players. The maximum anaerobic power was significantly greater in the JPN players than in the OL players (p<0.05) and the JSL players (p<0.05), and the anaerobic power per kilogram of body weight was significantly higher in the JPN players than in the JSL players (p<0.01) . There was no significant difference in the 40 seconds power among the three groups. These results suggest that the JPN players have greater muscle power than the OL or JSL players because of the differences in the muscle mass.