The fact that flip-flops, one of many different types of unstable shoes, are light and relatively easy to put on, accounts for their popularity among people. But because flip-flops rely heavily on the support of a single thong between your first and second toes, they impose a huge amount of pressure onto lower leg. Thus in the following experiment we tried to examine the different effects of flip-flops and running shoes in terms of their effect on muscle activity and fatigue of tibialis anterior and gastrocnemius during walking. In order to measure an electromyogram we used Free EMG system. 10 men and 10 women in running shoes ran on treadmills for 15 minutes at 4.8km/h, 2 days later the same experiment was carried out, but this time, in flip-flops. p value turned out to be greater than .05 and thus there was no considerable difference between the effects of flip-flops and running shoes on muscle activity and fatigue during walking. Therefore we conclude that despite the fact that flip-flops are considered unstable, their effects on muscle activity and fatigue of tibialis anterior and gastrocnemius are negligible.

The purpose of this study was to examine the influences of chronic shoulder pain on the muscle tone in trunk muscles. The study's subjects were 40 men and women in their 30 to 50s, which were divided into two groups. A chronic shoulder pain group consisted of 20 subjects who had been diagnosed with chronic shoulder pain by doctors, and a painless group consisted of 20 subjects who had experienced no such pain. An analysis was performed using electromyography on the muscle tone in the rectus abdominalis, external oblique, internal oblique, and erector spinae muscles under the same conditions between the two groups. The analysis results were as follows. The chronic shoulder pain group exhibited an overall high level of trunk muscle tone than the painless group, along with a statistically significant difference in the rectus abdominalis(p<.05). Moreover, the chronic shoulder pain group showed differences in the trunk muscle tone depending on the affected side. The chronic left shoulder pain group yielded higher levels of muscle tone in the right-side trunk muscles. In particular, the group revealed statistically significant differences in the rectus abdominalis and internal oblique(p<.05). The chronic right shoulder pain group exhibited higher levels of muscle tone in the left-side trunk muscles with a statistically significant difference in the internal oblique(p<.05). The above results suggested that chronic shoulder pain influences increases in the muscle tone in the trunk muscles on the opposite side to the affected shoulder.

Inflorescence, stem, and leaf samples of lettuce grown in a greenhouse in spring and autumn seasons were assayed for sesquiterpene lactones (SLs) content by high performance liquid chromatography. The concentrations of SLs were significantly higher in the inflorescences followed by upper leaf and stem compared to the other plant parts in most of the samples. SLs content (sum of lactucin and lactucopicrin) in various tissues of lettuce cultivated in spring season varied from 5.7 to 22.5 fold ranging from 27.4 ㎍/g dry weight (DW) in the upper stem (cultivar “PI 176588”) as the lowest to as high as 2,292.0 ㎍/g DW in the inflorescence (cultivar “709849-1”). During autumn cultivation, the concentration of SLs varied from 2.0 to 14.4 fold ranging from as low of 32.4 ㎍/g DW in the lower stem (cultivar “PI176588”) to as high of 838.0 ㎍/g DW in the upper leaf (cultivar “Dambaesangchu”). Higher lactucin (1.2 to 5.6 fold) and lactucopicrin (1.1 to 3.9 fold) concentration was observed during spring compared to autumn cultivation in most of the samples. SLs content in various organs of lettuce increases from the basal plant part going upwards. As lactucin and lactucopicrin are the major SLs which affects the sensory property of lettuce, their quantitative variation in the lettuce cultivars is useful for breeding new varieties with better consumer acceptance.