Since The Start Of The "grass-cutting" Season, I Have Been

Since the start of the "grass-cutting" season, I have been experiencing a tightness in my left calf muscle when I first begin the mowing process, which then dissipates after approximately 15 minutes. In addition, there is a noticeable atrophy in the calf muscle & quad muscle above the knee. I believe this is a vascular issue, as I have had an Arterial Doppler with exercise (decreased blood flow to left leg apparently originating where femoral artery branches off from main trunk artery) & a "negative" EMG. What would be the next course of action?