The influence of aerobic and anaerobic components of muscular endurance on the lower limbs, on sprint ability while under conditions of muscular fatigue, was investigated. Fifteen track and field athletes (400 m sprinters, decathletes and middle distance runners) participated in the study in which running and sprinting movements at respective points (360 m and 50 m) along two distance conditions (400 m and 80 m, respectively), were filmed by high-speed video camera. Running speeds at each point were computed from the film analysis. The running speed at 360 m point was defined as the speed under fatigue, while the running speed at the 50m point was defined as the maximal speed. Further, the rate between speed under fatigue and maximal speed was defined as %Max. Speed. Maximal O₂ intake, O₂ debt and isokinetic muscular endurance were measured.
The results were summarized as follows :
1) Oxygen debt showed significant correlation with the average speed during 400m running (r=0.546 ; p<0.05), but not with the speed under fatigue (r=0.388 ; p>0.05) .
2) Speed under fatigue was positively correlated with muscular endurance of hip flexion and extension (r=0.683 ; p<0.01, r=0.572 ; p<0.05) .
3) Percent Max. Speed was negatively correlated with the maximal speed (r = -0.643 ; p <0.01) and positively correlated with the muscular endurance of hip flexion and extension, and knee flexion (r=0.640 ; p <0.05, r=0.517 ; p<0.05, r=0.646 ; p<0.01) .
These results suggest that; raising %Max. Speed to improve the muscular endurance of lower limbs and, to improve aerobic ability by developing the number of capillaries in the muscle, is important.

In Hokkaido, the number of work-related deaths has been decreasing owing to increased safety measure implementation. However, safety measures for non-life-threatening injuries are considered to be insufficient. To reveal the status of non-life-threatening work-related injuries in Tokachi district, we investigated patients with work-related injuries who visited the Orthopaedic Surgery Department of our hospital, which has the only Emergency and Critical Care Center in the district, and examined in detail patients who needed multiple operations. All patients in the Department of Orthopaedic Surgery who had worker’s accident insurance were included in this study. We investigated age, sex, occupation, injury cause, injury site (upper extremity, lower extremity, and/or spine), diagnosis, and number of operations. There were 818 cases of work-related injuries and mean age was 47 (16-82) years. Regarding injury site, 482 patients had upper extremity injury, 273 had lower extremity injury, and 123 had spinal injury. Regarding number of operations, 371 patients had operations and 37 (28 upper extremity injuries and 11 lower extremity injuries) underwent operations more than 3 times. In 19 cases, injuries were caused by the primary industry of employment and 14 by a secondary industry; 19 cases were due to the patient being caught in an industrial machine, mostly agricultural harvesters. Severe injury requiring surgery occurred more than 3 times involved complex injury in the upper extremity or open fracture with soft tissue defect. In Tokachi district, severe limb injury is typically accompanied by soft tissue damage and requires long-term treatment including multiple operations. In future studies, it will be important to conduct detailed evaluation of non-life-threatening work-related injuries, including severe limb injury, and to establish relevant safety measures for such injuries especially those occurring in agricultural workers.

The balance between treatment and farming work must be considered when performing hand surgery in farmers, but no studies have previously examined the level of busyness in farmers in detail. We conducted a questionnaire survey on busyness by month and desirable time for hand surgery in 20 self-employed farmers in the Tokachi region of Hokkaido who had undergone hand surgery. Busyness in crop farming peaked approximately in May for fertilizer application, sowing, and raising and transplanting seedlings and in August-October for harvesting and transporting crops. On the other hand, livestock farmers were busy with rearing management throughout the year, with a peak of busyness in May-October for fertilizer application, sowing, and harvesting and transporting forage crop. Given the approximately 3-month period of work restriction following hand surgery, all respondents wished to have this period from November to January. If a farmer is injured during the peak farming period, a treatment plan is required that supports an early return to work and allows for two-stage reconstruction and treatment of degenerative disease in the quiet period for farming. Meanwhile, almost no respondents expected to receive support from official organizations and manufacturers, indicating that there is a need to provide the government with information from a medical perspective.

When treating finger, hand, and elbow trauma (hereinafter, surgically treated hand trauma) in self-employed farmers, it is also necessary to consider how the patient will be able to continue working in the family business. This study investigated return-to-work outcomes of self-employed farmers in the Tokachi area in Hokkaido, Japan after surgically treated hand trauma. A survey was conducted with 56 self-employed farmers (39 men and 17 women, median age 55 years). More than 80% of the farmers (n = 49) returned to their previous work, and most returned to work during the farming season while still experiencing functional impairment. Self-employed farmers with surgically treated hand trauma tend to return to work in time for the farming season regardless of the severity of functional impairment they are experiencing, and it is important for health care providers to recognize this fact and consider return-to-work support as part of the treatment plan in addition to treatment itself. Therefore, providers must understand the processes and details of tasks performed during each farming season and devise individualized measures to accommodate patients returning to work while still experiencing impairment. In cases where multiple treatments are required, such as two-stage functional reconstruction, it is also important that the treatment plan consider the farming season, for example, by having the patient temporarily return to work and then undergo surgery during the off season.