The purpose of this study was to investigate the effect of different types of mechanical stimulation of the sole on standing postural stability in healthy, young adults. Fifty subjects (34 women, 16 men; mean age 23 ± 2 (mean ± SE)) stood barefoot on fixed force plates both with open and closed eyes on firm surface and then on compliant surface (foam). A modified clinical test of sensory interaction on balance protocol was employed to assess the center of gravity (COG) excursions along anteroposterior (AP) and mediolateral (ML) axes on each surface and visual condition. After the baseline measurement, a stimulation was applied with an elastic spiked layer topped to the firm and then foam surface, and the COG excursions were measured during the stimulation, and then at least 30 min after the stimulation of the spiked layer, we used 10 min of manual static and glide pressure applied to the plantar surface of both feet. Immediately after manual stimulation, static balance parameters were measured again. Results showed that after manual stimulation, the sway path with closed eyes decreased significantly on the AP and ML directions on firm surface conditions. The spiked layer caused significantly decreased sway path on firm platform in both directions, but it was ineffective on compliant surface. Our results established that the activation of plantar mechanoreceptors by 10-min manual stimulation can partially compensate subjects for the absence of visual input and the lack of accurate pressure information from the supporting surface, too.

Our data revealed that the manipulation of both visual and somatosensory information can reveal subtle impairments in balance control. Thus, this paradigm can unmask the effects of decreased proprioception due to joint capsule lesion in patients with rheumatoid arthritis.

1. Chronic pain owing to arthritis is a major clinical problem worldwide. To study the underlying pathological mechanisms of chronic pain and the effectiveness of different treatments, a number of experimental models have been developed over the years. 2. We introduced a new subchronic inflammatory model by repeated unilateral administration of carrageenan into the ankle joint of rats, and investigated the degree and the time-course of the oedema, and thermal and mechanical hyperalgesia. 3. Carrageenan (450 microg) was injected on three occasions (on days 1, 4 and 7), and the resulting oedema, thermal hyperalgesia (paw withdrawal test) and weight load were characterized in voluntarily walking rats daily for 15 days. The effect of diclofenac sodium (3 mg/kg orally daily for 15 days) was also determined. 4. Repetitive administration of carrageenan caused fluctuating oedema and pain responses, which did not normalize within 3 days. Exacerbated inflammatory oedema was observed after the second and third injections. Oedema and a decreased weight load of the inflamed paw were observed throughout the investigation period, and paw withdrawal thresholds to noxious thermal stimuli returned to baseline pre-carrageenan values from Day 13. 5. Oral diclofenac (3 mg/kg daily for 15 days) significantly decreased oedema within a few days (Day 3), whereas its anti-allodynic effect developed only several days later (Day 9). However, diclofenac at the applied dose did not influence the thermal hyperalgesia. 6. The results suggest that the repeated administration of carrageenan might be a suitable model for determining the effects of long-lasting treatment.

As proprioceptive training is popular for injury prevention and rehabilitation, we evaluated its effect on balance parameters and assessed the frequency spectra of postural sway linked with the various sensory channels. We recorded the Center of Mass displacement of 30 healthy student research participants (mean age = 21.63; SD = 1.29 years) with a single force plate under eyes open (EO) and eyes closed (EC) positions while standing on either a firm or foam surface, both before and after an 8-week balance training intervention on a foam surface with EC. We subjected the data to frequency power spectral analysis to find any differences between the frequency bands, linked with various sensory data. On the foam surface in the EC condition, the sway path decreased significantly after proprioceptive training, but, on the firm surface in the EC condition, there was no change. On the foam surface in the EC condition, there was also a significant decrease in frequency power postproprioceptive training in the medium-to-low frequency band. While our data indicate better posttraining balance skills, improvements were task specific to the trained condition, with no transfer of the acquired skill, even to a similar, easier condition. As training improved the middle-low frequency band, linked with vestibular signals, this intervention is better described as balance than "proprioceptive" training.

The authors emphasize the role of physical exercises in the prevention and treatment of osteoporosis through reviewing the most important evidences. With the increase of life expectancy, it becomes more and more challenging to fight against osteoporosis related fracture complications and functional restrictions. The article gives an insight into the different physical exercises that are able to influence the condition as prevention and also as treatment possibilities without having adverse side effects. Since improving balance and postural control are essential part of the interventions and they are under the influence of multiple sensory, motor and cognitive systems, this multisystem nature of balance should take into account in falls prevention even in terms of osteoporosis.