To investigate the relationship between maximal aerobic power (VO₂max) and fatigu-abililty during repeated isokinetic contractions, 39 male speed skaters (mean 20.8 years) served as subjects. They were divided into two groups according to their VO₂max levels ; high VO₂max group (HI, n=19) and low VO₂max group (LO, n=20) . VO₂max was measured in all subjects during incremental exercise on a bicycle ergometer and body composition was determined by densitometry. Cross-sectional area (CSA) of the leg extensor muscles was evaluated using ultrasonic method. Fatiguability was assessed during the fatigue test consisting of 50 repeated isokinetic knee-extensions at an angular velocity of 180 deg⋅sec^-1. Remark-able findings include :
1. There were no significant differences in body composition and thigh composition between the two groups except for high subcutaneous fat in group LO.
2. There were significant differences in VO₂max between group HI (3.93l⋅min^-1, 67.3 ml⋅kg LBM^-1⋅min^-1) and group LO (3.59l⋅min^-1, 59.9 ml⋅kg LBM^-1⋅min^-1) .
3. In the fatigue test, the average initial values did not differ, however, the average final values were higher in group HI. Also, a significant difference was observed in per unit CSA between the two groups.
4. Higher peak forces (kg) in group HI were observed after the initial 30 dymanic contractions per unit CSA and % of peak values (% peak force) .
5. A close relationship was demonstrated between VO₂max per LBM and the fatigue index, i. e., the mean decline in peak force with 50 contractions (r=-0.37, p<0.05) .
Based on the present findings it is suggested that maximal aerobic power (VO₂max) influences the rate of fatigue development even during short-term maximal isokinetic contractions, and that there may be some physiological cross-linkages between cardiopulmonary regulation and the metabolic properties of skeletal muscles. This finding is also in conformity with earlier results indicating the importance of oxygen delivery as a limiting factor for muscle performance.

A 28-year-old woman with no underlying health issues was injured in a motorcycle accident and taken to our hospital by ambulance when she was 26 years old. Though she was diagnosed with multiple trauma, upon arrival at the hospital neither cardiac murmurs nor cardiac abnormalities on transthoracic echocardiography were detected. She was managed conservatively, and discharged on hospital day 16. She experienced dyspnea upon mild effort, and an early diastolic murmur appeared. She was again referred to our hospital, and diagnosed with severe aortic regurgitation. We scheduled an aortic valve replacement using an bioprosthetic valve because she intended to give birth. We also considered simultaneous aortic root enlargement as her aortic annulus was small. We performed the surgery 2 years after the initial motorcycle accident. Perioperatively, we noticed that her non-coronary cusp was torn. We converted the procedure to an aortic valve repair using an autologous pericardial patch. Her aortic regurgitation disappeared after the operation, and she was discharged on postoperative day 14. We successfully preserved the aortic valve cusps and avoided the need for anticoagulant therapy.