INFLUENCE OF ALTERING BREATHING TECHNIQUES ON PASSIVE DRAG: A PRELIMINARY REPORT

The purpose of this study was to examine if passive drag could be altered by adopting different breathing techniques; chest breathing technique and abdominal breathing technique. Six male subjects participated in this study. Each Subject was towed at a constant towing force in the glide position with inflating their chest or abdomen. The steady-state velocity was measured and the drag coefficients was calculated for each breathing technique. Results showed that the towing velocity was significantly greater with abdominal breathing technique than with chest breathing technique (

A preoperative simulation of medial open-wedge high tibial osteotomy for predicting postoperative realignment

Three-dimensional preoperative surgical simulation of the medial open-wedge high tibial osteotomy (OWHTO), simplified as the rigid rotation around the hinge axis, has been performed to predict postoperative realignment. However, the practicality of this highly simplified simulation method has not been verified. This study aimed to investigate the validity of realignment simulation simplified as a rotation around a hinge axis compared with a postoperative CT model. A three-dimensional surface model of the tibia and femur was created from preoperative computed tomography (CT) images (preoperative model) of three patients. The simulation of medial OWHTO created sixty computer simulation models in each patient simplified as the rigid rotation of the proximal part of the tibia relative to the distal part from 1° to 20° around three types of hinge axes. The simulation models were compared with the actual postoperative model created from postoperative CT images to assess the reality of the simulation model. The average surface distance between the two models was calculated as an index representing the similarity of the simulation model to the postoperative model. The minimum value of average surface distances between the simulation and postoperative CT models was almost 1 mm in each patient. The rotation angles at which the minimum value of average surface distances was represented were almost identical to the actual correction angles. We found that the posterior tibial tilt and the axial rotation of the proximal tibia of the simulation model well represented those of the postoperative CT model, as well as the valgus correction. Therefore, the realignment simulation of medial OWHTO can generate realistic candidates for postoperative realignment that includes the actual postoperative realignment, suggesting the efficacy of the preoperative simulation method.Konda S., Ishibashi T., Tamaki M., et al. A preoperative simulation of medial open-wedge high tibial osteotomy for predicting postoperative realignment. Frontiers in Bioengineering and Biotechnology 11, 1278912 (2023); https://doi.org/10.3389/fbioe.2023.1278912

Tibial morphology of symptomatic osteoarthritic knees varies according to location: a retrospective observational study in Japanese patients

Ishibashi T., Konda S., Tamaki M., et al. Tibial morphology of symptomatic osteoarthritic knees varies according to location: a retrospective observational study in Japanese patients. Scientific Reports 14, 3250 (2024); https://doi.org/10.1038/s41598-024-53222-w.This study analyzed 31 patients with symptomatic osteoarthritic knees scheduled to undergo knee arthroplasty or high tibial osteotomy and demonstrated shape variations in their proximal tibia using an average three-dimensional (3D) bone model. Preoperative computed tomography of the affected knees was reconstructed as 3D bone models using a triangle mesh of surface layers. The initial case was defined as the template, and the other models were reconstructed into homologous models with the same number of mesh vertices as that in the template. The corresponding mesh vertices of the other models were averaged to evaluate the spatial position on the particular mesh vertex of the template. This was applied to all the mesh vertices of the template to generate the average 3D model. To quantify the variation in surface geometry, average minimum distance from the average bone model to 31 models was recorded. The medial proximal tibial cortex (1.63 mm) revealed lesser variation compared to the tibial tuberosity (2.50 mm) and lateral cortex (2.38 mm), (p = 0.004 and p = 0.020, respectively). The medial tibial plateau (1.46 mm) revealed larger variation compared to the lateral tibial plateau (1.16 mm) (p = 0.044). Understanding 3D geometry could help in development of implants for arthroplasty and knee osteotomy

Characteristics of physical activity during beginner-level group tennis lessons and the effect daily activity

Kawakami R., Yamakawa S., Konda S., et al. Characteristics of physical activity during beginner-level group tennis lessons and the effect daily activity. Scientific Reports 14, 249 (2024); https://doi.org/10.1038/s41598-023-46843-0.Tennis is a popular leisure sport, and studies have indicated that playing tennis regularly provides many health benefits. We aimed to clarify the characteristics of physical activity during beginner-level group tennis lessons and daily physical activity of the participants. Physical activity was measured using an accelerometer sensor device for four weeks, including the 80-min duration tennis lessons held twice a week. Valid data were categorized for tennis and non-tennis days. The mean physical activity intensity during the tennis lesson was 3.37 METs. The mean ratio of short-bout rest periods to the tennis lesson time in 90 and 120 s was 7% and 4%, respectively. The mean physical activity intensity was significantly higher (p < 0.0001) and the duration of vigorous-intensity physical activity (VPA) was increased in 76% of participants on days with tennis lessons compared to without tennis lessons. Beginner-level tennis lesson has characteristics of less short-bout rest physical activity than previously reported competitive tennis match and increased the duration of VPA in daily activity compared to without tennis lessons, suggesting that beginner-level tennis lessons contribute physical activity of health benefits