Effects of plantar intrinsic foot muscle strengthening exercise on static and dynamic foot kinematics: A pilot randomized controlled single-blind trial in individuals with pes planus.

BACKGROUND: No reliable evidence has confirmed whether plantar intrinsic foot muscle strengthening exercises improve static and dynamic foot kinematics in individuals with pes planus. RESEARCH QUESTION: Does the short-foot exercise affect static foot alignment and foot kinematics during gait in individuals with pes planus? METHODS: This was a randomized controlled single-blind trial involving 20 participants with pes planus who were randomly allocated to a short-foot exercise group (exercise) or a control group (controls). Exercise patients performed a progressive short-foot exercise three times per week for 8 weeks; controls received no intervention. Before and after the 8-week intervention, foot kinematics during gait, including dynamic navicular drop-the difference between navicular height at heel strike and the minimum value-and the time at which navicular height reached its minimum value were assessed, using three-dimensional motion analysis. We assessed static foot alignment by foot posture index and navicular drop test, and the thickness of the intrinsic and extrinsic foot muscles using ultrasound. All measurements were performed by one investigator (KO) blinded to the participants' allocation. RESULTS: After the 8-week intervention in the exercise group, foot posture index scores with regard to calcaneal inversion/eversion improved significantly (p < 0.05). Moreover, the time required for navicular height to reach the minimum value decreased significantly (p < 0.01). SIGNIFICANCE: For individuals with pes planus, the short-foot exercise effectively corrected static foot alignment and temporal parameters of foot kinematics during gait. This temporal change, which shortens the time for navicular height to reach its minimum value, indicates an improved windlass mechanism. Therefore, short-foot exercise might effectively prevent or treat injuries related to the pes planus alignment.

The recovery time required for rat joint contractures treated with joint fixation with unweighting of the hind limbs.

[Purpose] The purpose of this study was to investigate whether the recovery period of joint contractures differ between treatments with joint fixation with unweighting of the hind limbs and joint fixation alone. [Subjects and Methods] Twelve 10-week-old male Wistar rats were divided into a group with joint fixation of the right ankle joints in full plantar flexion for 1 week (F) and a group with joint fixation and hind limb suspension (FS). Thereafter, the rats were removed from the joint fixation and hind limb suspension for 2 weeks. The ankle dorsiflexion angles during the recovery process of the joint contractures were measured. [Results] The ankle dorsiflexion angles of the F group from the day joint fixation was removed to the seventh recovery day were significantly lower than the pre-experiment values. The ankle dorsiflexion angles of the FS group from the day joint fixation and hind limb suspension were removed to the 10th recovery day were significantly lower than the pre-experiment values. [Conclusion] We found that the period required for the recovery of joint contractures treated with joint fixation with unweighting of the hind limbs was longer than that with joint fixation alone.

The effect of additional activation of the plantar intrinsic foot muscles on foot kinematics in flat-footed subjects.

BACKGROUND: Strengthening exercises of the plantar intrinsic foot muscles (PIFMs) are often prescribed to flat-footed subjects because of the capacity of the PIFMs to support the medial longitudinal arch (MLA). However, it is unclear whether the capacity of the PIFMs to support the MLA is enough to change the foot kinematics in flat-footed subjects. To confirm this, the current study examined changes in foot kinematics in flat-footed subjects during standing and gait accompanied by changes in the activity of the PIFMs. METHODS: Eighteen flat-footed subjects were randomly assigned to an electrical stimulation group (ESG) or a control group (CG). In the ESG, electrical stimulation to the PIFMs was applied during standing and gait to simulate reinforcement of the PIFMs. Then, foot kinematics were measured using 3D motion analysis, and the amount of change from baseline (when no electrical stimulation was applied) was compared between the groups. RESULTS: In the gait analysis, the time at which the MLA height reached its minimum value was significantly later in the ESG, with no reduction in the MLA height at that time. Moreover, forefoot inversion angle and tibial external rotation angle were significantly increased in the ESG at that time. In the standing analysis, there were no significant differences between the groups. CONCLUSION: The results revealed that in flat-footed subjects, the PIFMs have the capacity to support the MLA enough to change foot kinematics during gait. Strengthening these muscles may be effective in preventing or treating lower extremity overuse injuries related to flat-foot alignment.

Study on change of rat soleus extensibility caused by reduction in joint movement with unweighting of the hind limbs.

[Purpose] The purpose of this study was to investigate the change in soleus extensibility from a joint contracture caused by a reduction in joint movement with unweighted lower limbs and to interpret the results to aid in the treatment of human joint contractures. [Subjects and Methods] The subjects of this study were twenty-one 10-weeks-old male Wistar rats. Twenty-one rats were divided into one control (C) and two experimental groups. The first experimental group included fixed right ankle joints in full plantar flexion (F). The second experimental group's hind limbs were suspended and the right ankle joints were fixed in full plantar flexion (FS). The period of this study was one week. On the first and last day of this study, all of the rats' ankle dorsiflexion angles were measured. On the last day of this study, all of the rats' soleus extensibilities were measured. [Results] On the last day of this study, the ankle dorsiflexion angles and the soleus extensibility in the FS group were significantly more decreased than those of the F group. [Conclusion] It was shown that the skeletal muscle extensibility from joint contracture caused by reduction of joint movement with unweighted lower limbs was more markedly decreased than that from joint contracture caused by reduction of joint movement.

Effects of joint immobilization and hindlimb unloading on collagen fibers of soleus muscles in rats.

[Purpose] The purpose of this study was to determine whether collagen fibers cause a difference in a contracture resulting from a combination of joint fixation and hindlimb unloading as compared to joint fixation only. [Subjects and Methods] The subjects of this study were 21 female Wistar rats divided into 4 groups as follows: Control Group (CON, n=7); Joint Fixation Group (JF, n=7), Hindlimb Unloading Group (HU, n=7), Joint Fixation Plus Hindlimb Unloading Group (JF+HU, n=7). This study was conducted for 1-week. Ankle joint range of motion and positive areas of collagen using fluorescent stain were analyzed. [Results] Ankle joint range of motion in JF + HU showed an increase compared to that of JF. Positive areas of Type I collagen in JF+HU showed an increase as compared with that of JF. [Conclusion] The results of this study suggested that the difference in a contracture caused by only joint immobilization and by a combination of joint immobilization and hindlimb unloading were significantly associated with Type I collagen.

A study of the relationships of changes in pain and gait after tourniquet-induced ischemia-reperfusion in rats.

[Purpose] The purpose of this study was to determine the relationships of changes in pain and gait after ischemia reperfusion was induced by tourniquet in rats. [Subjects and Methods] The subjects were six ten-week-old male Wistar rats. Ischemia was induced in the left lower limbs of the experimental rats at a pressure of 300 mmHg for 90 minutes. Pain behavior evaluations were measured using the von Frey test in all the rats' hind limbs. A consistently increasing plantar stimulus was applied until the rats exhibited an escape behavior. For the evaluation of gait, a two-dimensional motion analysis system was used to measure the distance from the calcaneus to the floor (DCF) and toe extension angle (TEA) during gait. The evaluations were performed in the normal state, 3 hours after ischemia-reperfusion, and daily until 7 days after ischemia-reperfusion. [Results] Compared with the normal state, the means of the pain threshold showed a significant decrease until 4 days after ischemia. In addition, both TEA and DCF continued to show a significant decrease at 7 days after ischemia as compared with the normal state. [Conclusion] This study revealed that hyperalgesia occurs after ischemia-reperfusion, and recovery of hyperalgesia occurred earlier than gait dysfunction recovery.

Effects of skin stretching without joint movement on skin extensibility of rats.

[Purpose] This study examined the possibility of maintaining skin extensibility by stretching the skin involved in disuse joint contracture. [Subjects and Methods] The study was carried out using 18 male Wistar rats. The rats were randomly allocated to three groups. The control group received no intervention for the right ankle joint, the fixation group received one-week's fixation of the right ankle joint in maximum plantar-flexion with a cast, and the stretching group received continuous stretching of the skin over the Achilles tendon for 30 min once daily for one week with the cast removed during the skin stretching, but the joint was not moved. On the final day, skin extensibility of the skin from the posterior aspect of the ankle joint was determined using a tensile strength tester and a length-tension curve. [Results] Statistical analysis of the data revealed significant differences in the skin extensibility among the three groups. The stretching group showed significantly greater improvement of skin extensibility than the fixation group. [Conclusion] Skin stretching without moving the joint was demonstrated to be useful for maintaining skin extensibility.

Study on changes in skin extensibility during the development of joint contracture due to joint immobilization in rats.

[Purpose] The purpose of this study was to elucidate whether skin extensibility decreases when a contracture develops as a result of joint immobilization. [Subjects] This study was conducted on six female Wistar rats. [Methods] The rats were divided into two experimental groups. In the immobilized group, the right ankle joints were immobilized in complete plantar flexion by plaster casts for two weeks. In the control group, the left ankle joints had no intervention. On the final day, skin extensibility was determined from a length-tension curve by collecting skin from the posterior aspect of the ankle joint and using a tensile strength tester. [Results] Compared with the control group, the immobilized group showed a significant decrease in skin extensibility. [Conclusion] The results demonstrated that the extensibility of the skin itself decreases when joint contracture develops.

Effect of stretch on improvement of muscular contractures in rats.

[Purpose] The purpose of this study was to investigate how a stretching torque affects muscular contractures. [Subjects] The subjects of this study were 48 male Wistar rats. [Methods] Subjects were divided into 4 groups as follows: Group 1 was the control; Group 2 had muscles in continuous fixation; Group 3 had muscles stretched in the direction of dorsiflexion by a spring balancer set at a torque of 0.3N for a period of 30 minutes after continuous fixation; and Group 4 had muscles stretched in the direction of dorsiflexion by a spring balancer set at a torque of 3.0N for a period of 30 minutes after continuous fixation. Joint fixation periods were for 2 and 4-weeks. Ankle joint range of motion and soleus flexibility were analyzed. [Results] For the 2-week joint fixation, soleus flexibility in Group 4 showed an increase compared with that of Group 3. For both fixation periods, range of motion in Group 4 showed an increase compared with that of Group 3. [Conclusion] For both fixation periods, stretching improved joint range of motion. In the 2-week joint fixation, soleus flexibility improved. However, soleus flexibility did not improve in the 4-week joint fixation.

Aerobic interval exercise with an eccentric contraction induces muscular hypertrophy and augmentation of muscular strength in rats.

[Purpose] The purpose of this study was to examine whether an aerobic interval exercise using an eccentric contraction would result in skeletal muscular hypertrophy and augmentation of muscular strength in rats. [Subjects and Methods] Twenty-one female Wistar rats were used in this study. The rats were randomly divided into three groups. The control group performed no exercise. The aerobic endurance exercise group ran for 90 min. The aerobic interval exercise group ran for a total of 90 minutes in 5 minute bouts separated by 2 minute rest periods. The exercise groups ran on a downhill treadmill incline, once every three days, for a total of twenty sessions. [Results] The muscle wet weights, the muscle fiber cross-section minor axes, and the tetanus tension results of the aerobic endurance and aerobic interval exercise groups were significantly larger than those of the control group. [Conclusion] These results indicate that aerobic interval exercise may be an effective method of inducing hypertrophy and augmenting muscular strength in skeletal muscle.

Preventive effects of antioxidants and exercise on muscle atrophy induced by ischemic reperfusion.

[Purpose] This study aimed to determine whether muscle atrophy induced by ischemic reperfusion injury in rats can be prevented by the administration of antioxidants and exercise. [Subjects] Rats were randomly divided into five groups: non-treated, ischemic, exercise, ascorbic acid and exercise, and tocopherol and exercise. [Methods] The relative weight ratio of the soleus muscle and the length of the soleus muscle fiber cross-section minor axis were used for the evaluation of muscle atrophy. Pain was assessed as the weight-bearing ratio of the ischemic side. A multiple comparison test and the paired t-test were used for the statistical analyses. [Results] Compared with the non-treated group, the relative weight ratios of the soleus muscle and the lengths of the soleus muscle fiber cross-section minor axis significantly decreased in the other groups. Excluding the non-treated group, the relative weight ratios of the soleus muscle were heaviest in the tocopherol and exercise group. Excluding the non-treated group, the lengths of the soleus muscle fiber cross-section minor axis were longest in the tocopherol and exercise group, followed by the ischemic, exercise, and ascorbic acid and exercise groups. The amount of antioxidant substances did not decrease on the weight-bearing ratio of the ischemic side. [Conclusion] In this study, using an experimental rat model, we confirmed that antioxidants and exercise effect muscle atrophy induced by ischemic reperfusion. The results show that muscle regeneration was facilitated by phagocytosis in the tocopherol and exercise group.

Induction of Muscle Hypertrophy in Rats through Low Intensity Eccentric Contraction.

[Purpose] The purpose of this study was to examine whether a low intensity exercise using an eccentric contraction would result in skeletal muscle hypertrophy in rats. [Subjects and Methods] Eighteen female Wistar rats were used in this study. The rats were randomly divided into three groups. The control group performed no exercise. The level group ran on a treadmill on a 0° incline. The downhill group ran on a treadmill on a -16° incline. The two exercise groups ran on a treadmill at 16 m/min for 90 minutes, once every three days for a total of twenty sessions. [Results] The muscle wet weights, the relative weight ratios, and the muscle fiber cross-section minor axes of the downhill group were significantly larger than those of the control and level groups. There were no differences in the muscle wet weights, the relative weight ratios, and the muscle fiber cross-section minor axes between the control group and the level group. [Conclusion] The stimulation from the low intensity eccentric contraction may have produced enough mechanical stress to induce muscle hypertrophy without the over-stressing that might have produced muscle fiber damage. These results indicate that this technique may be an effective method of inducing hypertrophy in skeletal muscle.

Considering the effects purchase food balance guide utilizing cable television has on the user.

OBJECTIVES: The aim of this study was to empirically investigate the needfulness of the Purchased Foodstuffs Balance Guide as designed for its users and also consider its influence on better dietary habits. METHODS: The participants included 89 students who attended City A's Senior Citizens' College, and the reality of their ICT and dietary habits were surveyed. Next, 27 cable television subscribers were asked to be monitors for testing the Guide. The study took place during a period of September 2013 to March 2014. RESULTS: The results indicated that, for the senior citizens, ICT use was centred on communication with their families and that their awareness or desire was a low in terms of the functions of information transmission, entertainment and receipt of services. Next, after using the Purchased Foodstuffs Balance Guide, its needfulness and its influence on better food habits were examined. As a result, the most frequent response by the participants was that they 'understood [their own] purchasing tendencies' (36.0%), followed by the three items: 'The Guide is useful for managing my nutrition', 'The Guide enabled me to know what foodstuffs are required to supplement my diet' and 'I became more careful about purchasing foodstuffs in a balanced way.' CONCLUSIONS: The study showed that 70% of the participants felt that the Purchased Foodstuffs Balance Guide was useful and make decisions when purchasing food using the Guide. This indicates the possibility that the Guide exerts a positive influence on users' awareness of nutritional balance, foodstuff purchasing choices and dietary habits.

Effect of skin resection on the improvement of joint contractures in rats.

The effect of skin resection on joint contracture was determined by comparing the first measurement of range of motion after cast removal and the second measurement after the skin resection. This study aimed to verify that both the joint movement during the measurement and skin affect range of motion. [Subjects] Twelve female Wistar rats were used. [Methods] The right hind limb ankle of each rat was immobilized in complete plantar flexion in a cast. In the resection group (n = 6), the skin of the right hind limb ankle was removed surgically, but not in the non-resection group (n = 6). In the resection group, the first measurement of the dorsiflexion angle was obtained after the cast was removed, and the second measurement was obtained after skin resection. In the non-resection group, both measurements of the dorsiflexion angle were obtained soon after the cast was removed. [Results] Compared with the non-resection group, the resection group showed a significant increase between the first and second measurements of range of motion. [Conclusion] These results show that range of motion is substantially affected by skin, in addition to joint movement, during measurement.

Effect of an Intermittent Eight-hour Joint Fixation Period on Joint Contractures in Rats.

[Purpose] It has been shown that an eight-hour joint fixation daily (i.e. for the remaining 16 hours, rats were set free in the cage without joint fixation) for one week induces a joint contracture. The purpose of this study was to investigate the difference between an 8 hours continuous joint fixation and an 8 hours intermittent joint fixation per day (two 4 hours joint fixations) in the development of joint contractures in rats. [Subjects and Methods] The subjects of this study were 34 Wistar rats. On the first day, all of the rats' right ankle dorsiflexion angles were measured. The right hind limbs of all the rats were fixed in plantar flexion, and then the rats were divided into three groups as follows: Group 1 was in continuous fixation for 24 hours a day; Group 2 was in continuous fixation for 8 hours a day; Group 3 was in intermittent fixation for 8 hours a day. The fixation was performed daily for seven consecutive days. On the last day, ankle dorsiflexion angles of all the rats were measured after the casts had been removed. [Results] The development of joint contractures was statistically significant for Groups 1 and 2. [Conclusion] Our results indicate that 8 hours a day of continuous fixation induces a joint contracture, but 8 hours a day of intermittent fixation does not.

Evaluation of the Lactate Threshold during Downhill Running in Rats.

[Purpose] The purpose of the present study was to investigate if lactate thresholds in rats could be accurately determined during downhill running in rats. [Subjects] Twenty-four female Wistar rats were used in this study. Rats were randomly divided into two groups: the level running group and downhill running group. [Methods] Catheters were inserted into the right external jugular veins of the rats. Two days after the operation, the rats performed incremental exercise tests. The level running group ran on a treadmill at a 0° incline; the downhill running group ran on a treadmill at a -16° incline. The lactate threshold was determined using the 2-line combination that minimizes the total sum of squares for fitting all data. [Results] Maximal running speeds and running speeds at the lactate threshold for the downhill running group were significantly higher than those for the level running group. [Conclusion] In this study, it was possible to accurately determine the lactate threshold during downhill running. These findings suggest that when the treadmill speed is the same, downhill running can be done at lower metabolic intensity than level running.