A simple model concept developed for the SSAB steel plant was tested on data for another plant. That plant had an L-shaped tundish for billet casting. A special tanks in series model was developed for the steel flow in that tundish. The rest of the model could be used without change. It consists of simple equations for heat loss in ladle and tundish, as well as for the effect of thermal stratification and drainage flows in the ladle. The model was verified against existing data from continuous temperature measurements. The results show that the model approach developed for the steel plant of SSAB can also give good predictions with a different plant and tundish design. A simple mixing model could be used even for a complicated tundish configuration.

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The purpose of this study was to examine the hand reaction force in backstroke start including new backstroke positions. The subjects were elite-backstroker (n=6). The instruments consisted of backstroke on water proof force platform. Two-dimensional motion analysis technique was used to collect motion data. As result, there were two peaks (peak 1 and peak 2) in the elite swimmer's hand reaction horizontal force. Elite swimmers pulled the strongly at peak1. The results suggest that the pulling a is important skill in backstroke starts. And in the comparison of the positions, significant differences were found between horizontal lower at peak1 and other at peak1 (p<0.05), however horizontal lower showed the slowest transition time at 5m. This study was the first to investigate hand reaction force during backstroke start motion. The data in the present study was contrary to the describing reported by many coaching books.

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Introduction: In racket sports, it is necessary to devise a gripping method that facilitates both the efficient transmission of power and injury prevention. This study quantified

pressure distribution (PD) in the hand using various gripping methods and investigated the relationship between these distributions and muscle activation.

Methods: In a laboratory setting, a

sensor was used to measure hand PD in 15 healthy adults during each task. Participants gripped the sensor device using three patterns with simultaneous electromyography (EMG) recordings from the extensor digitorum communis (EDC), extensor carpi radialis, flexor digitorum superficialis (FDS), and flexor carpi ulnaris (FCU). The device's hand-contact area was assigned anatomical regions, and the percentage PD of each region was calculated for each task. We compared the EMG in each pattern and analyzed the correlation between force and EMG.

Results: The main outcomes measured were EMG and PD. For radial and power grips, there was a significant relationship between EDC and

force (r = 0.52, 0.47). For the ulnar , there was a significant relationship between FDS and force (r = 0.55). Furthermore, the ulnar EDC activity was significantly lower than that of the power , and FCU activity was significantly higher than that of the radial (p < 0.05).

Discussion: The ulnar

had significantly lower EDC activity than the power and higher FCU activity, which is involved in the elbow joint's stability, than the radial . The ulnar may be effective in preventing injuries.

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[Purpose] The purpose of this study was to understand the relationship between hand power and muscle activation during power and pinch . [Subjects] Fifty healthy adults were randomly arranged into two groups. [Methods] Hand power was measured using a hand dynamometer and pinch was measured with a pinch gauge. Muscle activation was measured using electromyography. [Results] The results were as follows: the power group and pinch group showed a significant difference in hand strength, but there was no significant difference in muscle activation. [Conclusion] In conclusion, the power showed greater hand strength than the pinch . However, no significant difference was found between the activation of the forearm and hand muscles. In other words, increased strength did not necessarily mean increased muscle activation. Therefore, the pinch is a more effective method of exercise.

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要旨 握力測定において，その測定法と測定条件は測定値に影響を与える．握力測定において測定方法と測定条件が，握力へどのような影響を与えるのか，文献レビューを通して概括する．握力測定における測定方法と測定条件が，測定値に与える影響が明らかになれば，信頼性・妥当性の高い測定が可能となり，評価や治療効果の判定を正確に行うことが可能となる．

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Background & Aims : The aim of this study was to investigate dual-task interference on maximum force while performing a and lift task. Moreover, the influence of handedness on maximum force, and the relationship between maximum force and subjective difficulty were also investigated. Methods : Eleven subjects took part in the study. The study experiment was comprised of one single task and three dual tasks : 1) and lift task, 2) and lift task with single-leg stance, 3) and lift task with eyes closed, and 4) and lift task with calculation. The experiment was conducted in both hands separately. Maximum force of four fingers (dominant/non-dominant×thumb/index finger) was compared among tasks and between hands. Results : We found that maximum force was increased mainly by the cognitive dual task in both hands, and that there was no difference between hands in the same task. There was a positive correlation between the perceived difficulty and maximum force in the dominant hand. Conclusion : Our results suggest that maximum force could serve as an objective index for

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The contribution of physiological mechanisms involving force-exertion value during maximal repeated rhythmic muscle contraction work changes over time. The purpose of this study was to examine the reproducibility of force and muscle oxygenation kinetics with a decrease of the gripping force during maximal repeated rhythmic (RRG). Subjects were 10 males, aged 20–26 years (height 173.9±7.3 cm, body weight 71.5±11.2 kg). Each subject performed maximal repeated rhythmic as a target value with a target frequency of 30 grips·min⁻¹ for 6 min. The trial-to-trial reproducibility of Oxygenated haemoglobin (Oxy-Hb), Deoxygenated haemoglobin (Deoxy-Hb), Total haemoglobin (Total Hb) and force during the RRG (6 min) was very high (r_xy=0.919–0.966) and the decreasing pattern of the force-time curve was consistent. The cross correlation coefficients of the force (r_xy=0.985) and muscle oxygenation kinetics (Total Hb: 0.996, Oxy-Hb: 0.992, Deoxy-Hb: 0.995) in the pre-inflection phase (marked force decreasing phase) were very high, while these coefficients in the post-inflection phase (almost steady state phase) were low as compared with those in the pre-inflection phase. The trial-to-trial reliabilities of any parameter regarding were fair or high (ICC=0.686–0.927). The changing points of muscle oxygenation kinetics appeared before reaching an almost steady state, which showed a high reliability and they were considered to reflect the shift of physiological mechanisms. In particular, the intraclass correlation coefficients (ICC) for the time to reach maximum Deoxy-Hb and Oxy-Hb values and regression coefficient in an increasing phase of Oxy-Hb were very high (ICC=0.894–0.947). It was found that the trial-to-trial reproducibility of force and muscle oxygenation kinetics is very high during the whole 6 min in RRG, but is poor during the post-inflection phase. The reproducibility of the force and muscle oxygenation kinetics in the phase before reaching an almost steady state during RRG is fair, and the decrease of the force in this phase may be influenced by the muscle oxygenation kinetics.

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The aim of this study was to clarify the

strength and progress of development in infants aged 0 to 2 years old. The subjects were 396 infants and we measured their strength with dynamometer （T. K. K. 1269r） for the infants. Date on 313 subjects out of the 396 were analyzed. The average of strength was followed：0 to 5 months was 0.81 kg, 6 to 11 months was 1.05 kg, 12 to 17 months was 1.45 kg, 18 to 23 months was 1.72 kg, 24 to 29 months was 2.31 kg and 30 to 35 months was 3.00 kg. Significant difference between boys and girls were not shown. The relationships between strength and age was the most significant, then height and weight next to age. strength increased with age, as a result, we were able to draw the growth diagrams for development in infants aged 0 to 2 years old.

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The value of force is widely used for the brawn measurement in the physical strength examination because of its easy measurement. However, by use of the dynamometer being on the market, force is measured to only one direction, so it is doubtful whether various kinds of brawn can be measured. For example, the force to tennis racket seems to be different from the force measured by the dynamometer. Therefore, we developed the equipment to measure brawn gripping the cylindrical bject like tennis racket . Then we examined characteristics of both conven ional dynamometer and the newly developed equipment. As the result, for the ormer, width has an influence slightly on force, but, for the latter, iameter affects strongly as the human sense feels.

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Due to local bone loss, re-attachment of the greater trochanter is often difficult in revision total hip arthroplasty and pseudoarthrosis of the greater trochanter. We use the Dall-Miles cable system (DMCGS) for trochanteric fixation in 17 hips (ten hips with revision, five hips with T. H. R. and two hips with pseudoarthrosis of the greater trochanter). Post-operatively, the trochanter failed to unite in two hips, caused by failure of the position of the cable . In all other cases, good radiological and clinical results were achieved. Better results are obtained using the DMCGS in cases of trochanteric bone loss following hip surgery using trochanteric osteotomy.

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We studied the movement of center of gravity (CG) in young and aged subjects during maximum of right or left hand. Body-sway was recorded with stabilometry in rest-stand position and in maximum . The data from right-or left-handed young subjects were analyzed. Maximum power was not different between dominant hand and un-dominant hands. Total length (LNG) and total movement area of CG (REC AREA) during the measurements were significantly larger in maximum than in rest-stand. In right-handed subjects, LNG increased to 245% and 250% of rest-stand value, and REC AREA increased to 589% and 633% in right and left hand , respectively. In left-handed subjects, LNG increased to 186% and 188% of rest-stand value, and REC AREA increased to 400% and 533% in right and left hand , respectively. No significant difference of LNG and REC AREA was observed between right and left hand in either hand dominant subject Maximum did not affect CG in rest-stand. In aged subjects, maximum power was significantly less than in young subjects (48%). LNG and REC AREA in rest-stand were significantly larger in aged subjects than in young subjects (220% and 400%, respectively). They were not different during maximum with either hand. While aged subjects have difficulty of controlling CG in rest-stand, they have less problems to stabilize CG during maximum . These data indicated that dynamic movement of CG might be important to understand person's activity of daily living.

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Analysis of the factors which influenced the work load in handwriting were studied using the new apparatus for simultaneous measurement of and pen-point pressures developed by the author. Thickness of the pen holder was shown to be a factor which influenced the work load, and diameter of pen holder for minimum load was determined. Nature of the pen-point was also one of the factors, and it was shown that the ball-point pen gave the greatest load and felt-point pen gave the smallest load in three kinds of pen-points; ball-point pen, felt-tip pen and pencil. Number of copies also influenced the load to the upper extremities, and taking more than three copies gave excess work load to female workers.

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Summary: Background: Patients with hip fracture are limited as to physical activity. It is difficult to evaluate the physical function of the legs at admission; however, it is easy to measure

strength, which has been reported to be correlated with systemic muscular strength and physical function. The objective of this study was to investigate the utility of strength in predicting functional outcome after hip fracture.

Methods: Fifty-seven patients who underwent surgery for hip fracture were evaluated for height, weight, Body Mass Index (BMI),

strength, bone density (femoral neck), hemoglobin, Hemoglobin A1c (HbA1c), Hasegawa’s Dementia Scale-Revised (HDS-R), and albumin at admission and Functional Independence Measure (FIM) at discharge. Spearman’s rank correlation coefficient was used to evaluate the relation between strength and the above variables. Furthermore, factors of walking acquisition were analyzed by logistic regression analysis and decision-tree analysis.

Results: Correlation analysis showed that

strength was positively correlated with bone density at admission and FIM at discharge and negatively correlated with age. In the logistic regression analysis, the independent factor associated with walking acquisition was strength (OR 1.26; 95%CI 1.018-1.566; p=0.0339). In the decisiontree analysis, strength was the initial divergence variable for walking acquisition (the percentage with walking acquisition was 80.0% of the patients with strength ≧13.2 kg VS. 18.7% of the patients with strength < 13.2 kg).

Conclusions:

strength at admission was definitive in predicting the functional outcome of patients with hip fracture who underwent surgery.

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This study aimed to clarify the effects of changing to a short bat position from the long bat position on baseball bat swing timing, peak ground reaction force with the front leg, and activation of the upper and lower limb muscles.
  Nine male college baseball players participated in this study. By using a batting simulator, the coincident timing task was to swing the bat coincidentally with the arrival timing of a moving target by using the long or short bat position. The batter performed 10 sets of four swings for a total of 40 swings for the coincident timing task. During the four swings, the batter swung the bat by using the long position in the first, second, and fourth swings. Only in the third swing did the batter use the short position. The ground reaction force with the front leg was measured, and electromyograms of the upper and lower limb muscles were obtained during the coincident timing task.
  Our results indicated no significant differences in absolute and variable timing errors between the long and short bat positions. In contrast, the constant timing error was significantly increased with the short bat position. Moreover, the time to peak ground reaction force and time to peak muscle activation of both the upper and lower limb muscles were significantly delayed when the short bat position was employed. Significant positive relationships were observed between the constant timing error and time to peak ground reaction force, which showed differences between the second and third swings. No significant difference in swing time was observed between the long and short bat positions.
  These findings indicate that changing to the short bat position from the long bat position will not improve the batter's swing timing. Furthermore, changing to the short bat position could delay the batter's swing timing, probably because the change causes a delay in swing preparation.

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Electrical muscle stimulation (EMS)-based systems have been proposed in human augmentation studies for augmenting motor skills while playing sports and musical instruments. Healthy people with such EMS-based systems perform voluntary muscle contractions while the EMS is superimposed on their muscles. However, few studies have investigated the effect superimposed electrical stimulation has on voluntary contractions for muscle coordination (i.e., the intentional, orchestrated movement of multiple body parts) in particular. Therefore, we investigate the effect of superimposed electrical stimulation on muscle coordination when users perform maximal

force, in which muscle coordination of the forearm and shoulder muscles occurs. We conducted a user study with 20 participants to assess the effect by measuring their maximal force under three conditions: no-EMS, EMS application to the forearm, and EMS application to the shoulder. The mean results were 33.4 kgw (327 N) for no-EMS, 30.9 kgw (303 N) for EMS to the forearm, and 32.4 kgw (318 N) for EMS to the shoulder, and the medians were 34.7 kgw (340 N), 30.3 kgw (296 N), and 33.5 kgw (328 N), respectively. We determined that electrical stimulation superimposed on muscle coordination diminished force, and the effect size differed depending on where EMS was applied. The results suggest that we should consider users’ muscle coordination when designing EMS-based systems for human augmentation to avoid unintentionally diminishing their ability.

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Objective: The aim of this study was to investigate the impact of untreated hand diseases on hand

strength, a value that is commonly used as a diagnostic parameter for sarcopenia and frailty in geriatric populations. We hypothesized that individuals with untreated hand diseases would have lower strength than those without hand diseases.

Methods: A total of 240 individuals aged at least 65 years were recruited and divided into two groups based on the presence or absence of typical hand diseases.

strength was compared between the two groups separately for men and women using a t-test, with each group consisting of 60 women or 60 men.

Results: Both women and men in the hand disease group exhibited significantly lower

strength than those in the control group.

Conclusions: These findings suggest that untreated hand diseases have a negative impact on

strength, and this may introduce bias in the screening or diagnosis of sarcopenia and frailty. It is essential to consider the presence of hand diseases when measuring hand strength in older adults.

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In this study the effect of elbow flexion with forward flexion of the upper arm and shoulder rotation on the maximum voluntary contraction (MVC) of strength was investigated. Two directions (vertical and horizontal), three positions (left side, central and right) and five elbow flexion angles were taken as independent variables. The analysis of variances (ANOVA) was performed on the data collected. The results of the analysis showed that there was highly significant effect of the direction, front position of the wrist (the line in front of the right shoulder, centre of the chest and left shoulder using the right hand in the sagittal plane), and the elbow flexion angle on MVC strength. The left position has significantly low strength compared to the right position for right-hand participants. The two-way interactions of all the three main factors were found significant. The three-way interaction was not found significant. Further one-way ANOVAs showed that the effect of the direction (vertical/horizontal) was not found significant on any of the levels of the position and elbow flexion in the simple main effects analysis (p>0.05).

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日本の国民皆保険制度では、入院期間は経済的制約ではなく、医学的必要性のみによって決定される。しかし、この制度は標準的な入院期間を定めており、この基準を超えて入院が遅れた場合、病院は保険金の減額を余儀なくされる。このため、事故などによる入院期間の延長など、医療以外の要因に注意深く対処することが奨励されている。回復期リハビリテーション病棟（CRW）におけるリハビリテーション・プログラムは、この問題に対処するために考案されたものである。本研究の目的は、握力の経時的変化と、寝たきり状態から退院後に発生する事故の頻度との関係を調査することである。 研究は、2023年6月1日から8月30日まで、日本郊外にある200床の病棟で実施され、横断的観察研究であった。参加者は、入院後1週間以内に入院した成人患者で、医学的測定が困難な状態にある者、著しい視覚障害や前庭機能障害がある者、改訂長谷川式認知症スケールで10点以下の者は除外され、参加に同意した。 参加者の募集は、病院長の承認を得るとともに、病院の理学療法士を通じて適格な患者を探し出した。本研究では、体調不良による除外1名を含む42名中41名のデータを分析した。解析はintent-to-treatの原則を遵守し、欠損データのある参加者全員を対象とした。参加者は、一般整形外科疾患16名、脊椎疾患12名、脳血管疾患8名、廃用症候群4名、その他の疾患1名で、合計女性28名、男性13名であった。 その結果、握力達成時間には男女間で有意差があり、女性は男性よりも平均して早く最大握力に達した。最大握力達成時間が16秒だった異常値を除くと、有意差はなくなり、平均して女性の方が男性よりも早く最大握力に達することが示された。この研究では、最大握力達成時間を指標として用いることで、インシデントの可能性を有意に区別することができ、臨床的有用性が示唆されると結論づけた。 最大握力到達時間のカットオフ点は、女性が2.54秒、男性が4.23秒であり、女性の方が有意に短かった。最大握力到達時間のAUCは0.72を超え、握力情報のみによる把持事故頻度の推定よりも優れていた。

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