Correction: Motor planning error in Parkinson's disease and its clinical correlates.

[This corrects the article DOI: 10.1371/journal.pone.0202228.].

Isometric knee muscle strength measurement using a belt-stabilized hand-held dynamometer and an isokinetic dynamometer with and without trunk fixation: investigation of agreement of measurement values and factors influencing measurement.

[Purpose] The purpose of this study was to examine the agreement between the values obtained by using a hand-held dynamometer with a belt (belt-HHD) and an isokinetic dynamometer (IKD) for the measurement of isometric knee flexion and extension muscle strength. We also studied the factors influencing the measurement. [Participants and Methods] Overall, 26 healthy young adults (16 males, 10 females) participated in the study; the mean age was 21 years. Knee flexion and extension muscle strength were measured by three methods: 1) belt-HHD, 2) conventional IKD with the participant sitting on an attached chair (conv-IKD), and 3) modified IKD with the participant sitting on the same mat table as HHD (mod-IKD). [Results] In the measurement of knee extension, mod-IKD and conv-IKD showed a fixed bias and a proportional bias, conv-IKD and belt-HHD showed a fixed bias, and belt-HHD and mod-IKD showed a fixed bias. In the measurement knee flexion, conv-IKD and mod-IKD showed a proportional bias, belt-HHD and conv-IDK showed a fixed bias, and mod-IKD and belt-HHD showed a fixed bias. In each combination, the measured values were larger in the latter due to errors. However, the types and values of errors differed when analysis was conducted based on gender. [Conclusion] In order to increase the agreement between the values, it is necessary to revise the fixing method of the trunk, and the fixing method of the belt and the sensor pad in belt-HHD.

Motor planning error in Parkinson's disease and its clinical correlates.

This study aimed to investigate (a) motor planning difficulty by using a two-step test in Parkinson's disease (PD) compared with age-matched healthy subjects and (b) the relationship between motor planning difficulty and clinical factors. The two-step test was performed by 58 patients with PD with Hoehn & Yahr (H&Y) stage I-IV and 110 age-matched healthy older adult controls. In the two-step test, the participants estimated the two-step distance with maximum effort. Subsequently, they performed the actual two-step trial to measure the actual maximum distance. We calculated the accuracy of the estimation (estimated distance minus actual distance). In both groups, subjects who estimated >5 cm were defined as the overestimation group, and those who estimated <5 cm over- and underestimation were defined as the non-overestimation group. The overestimation group consisted of 17 healthy older adults (15.5%) and 23 patients with PD (39.7%). The number of patients with PD with overestimation was significantly more than that of healthy controls by Chi-squared test. H&Y stage and the Unified Parkinson's Disease Rating Scale (UPDRS) part II and III scores in overestimation group in PD patients were significantly higher than those in overestimation group in PD patients. Moreover, multiple regression using H&Y stage and UPDRS parts II and III as independent variables showed that the UPDRS part II score was the only related factor for the estimation error distance. Estimation error distance was significant correlated with UPDRS parts II and III. Patients with PD easily have higher rates of motor-related overestimation than age-matched healthy controls. In addition, UPDRS parts II and III expressed ability of activities of daily living and motor function as influences on motor-related overestimation. Particularly, multiple regression indicated that UPDRS part II directly showed the ability of daily living as an essential factor for overestimation.

The immediate effect of neuromuscular joint facilitation on the rotation of the tibia during walking.

[Purpose] The aim of this study was to investigate the change in tibial rotation during walking among young adults after neuromuscular joint facilitation therapy. [Subjects and Methods] The subjects were twelve healthy young people (6 males, 6 females). A neuromuscular joint facilitation intervention and nonintervention were performed. The interventions were performed one after the other, separated by a 1-week interval. The order of the interventions was completely randomized. The rotation of the tibia during walking was evaluated before and after treatment. [Results] The neuromuscular joint facilitation group demonstrated increased lateral rotation of the tibia in the overall gait cycle and stance phase, and decreased medial rotation of the tibia in the overall gait cycle, stance phase, and swing phase after the neuromuscular joint facilitation intervention. In the control group, there were no significant differences. [Conclusion] These results suggest neuromuscular joint facilitation intervention has an immediate effect on the rotational function of the knee.

Validity and reliability of isometric muscle strength measurements of hip abduction and abduction with external hip rotation in a bent-hip position using a handheld dynamometer with a belt.

[Purpose] This study aimed to investigate the relatedness, reliability, and validity of isometric muscle strength measurements of hip abduction and abduction with an external hip rotation in a bent-hip position using a handheld dynamometer with a belt. [Subjects and Methods] Twenty healthy young adults, with a mean age of 21.5 ± 0.6 years were included. Isometric hip muscle strength in the subjects' right legs was measured under two posture positions using two devices: a handheld dynamometer with a belt and an isokinetic dynamometer. Reliability was evaluated using an intra-class correlation coefficient (ICC); relatedness and validity were evaluated using Pearson's product moment correlation coefficient. Differences in measurements of devices were assessed by two-way ANOVA. [Results] ICC (1, 1) was ≥0.9; significant positive correlations in measurements were found between the two devices under both conditions. No main effect was found between the measurement values. [Conclusion] Our findings revealed that there was relatedness, reliability, and validity of this method for isometric muscle strength measurements using a handheld dynamometer with a belt.

Effects on ROM and joint position sense of the neck of two different interventions.

[Purpose] The purpose of this study was to evaluate whether neuromuscular joint facilitation (NJF) training is superior to NJF distal resistance training at improving the ROM and proprioceptive acuity of the neck. [Subjects] 10 healthy subjects (8 males, 2 females) participated in this study. [Methods] The participants were allocated to three groups: 10 in the control group, 10 in the NJF distal resistance training group, and 10 in the NJF training group. A miniature wireless motion recorder was used to record the maximum cervical range of motion and joint position error (JPE) before and after the interventions. The three interventions were tested on different days. [Results] No difference of ROM was observed among the three groups. A significant pre- to post-intervention decrease in JPE in extension was identified in the NJF group. No other significant differences were observed among the three groups. [Conclusion] The NJF training conferred remarkable benefits on the cervical JPE of healthy people. This result suggests that the best way to improve proprioceptive acuity is intervention together with proximal resistance training, such as NJF training.