Anything is better than nothing but why only focus on the legs and why only once a week? Lifting only once a week you're not going to gain much strength and you'll be more sore as you don't have enough frequency. Would running once a week provide you the results you want? What if you were a beginning runner? Wouldn't running just once a week leave you sore?
Here's an idea:
Do a total body routine three times a week lasting around 45 minutes total somewhat similar to the following:
Horizontal Press (BB or DB bench press, incline bench, pushups, machine, etc)
Horizontal Pull(DB or BB Row, inverted row, seated row and variations, machine, etc)
Vertical Press (DB or BB Shoulder Press, machine, other varations such as arnold press, etc)
Vertical Pull (lat pulldown variations, pullup varations, hi row, etc)
Quad Dominant Leg (squat, leg press, short Step Up, short lunge)
Ham Dominant (deadlift, rdl, glute ham raise, hi step up, long lunge)
Bicep Exercise (curls, lots of variations)
Tricep Exercise (extensions, lots of variations)
2-3 sets, 10-15 reps, total of 8 exercises, 60-90s rest.
Alan