Fitting issues: Pattern Alterations for Athletic Build

Remember the red shirt I made my husband for Valentine's Day?  He loves it and has worn it several times, but there is a fit issue still bothering me.  

Diagonal wrinkles from the armhole up towards the neck.  This is a common fit issue in RTW shirts for him as well.  I searched through all my books on fitting, and all of them say the problem is sloping shoulders.  Before I made this shirt, I had adjusted the shoulder slope several times and I really didn't think that was the problem.

The typical shoulder slope adjustment is to lower the shoulder line at the armhole edge, and then lower the armhole by the same amount to preserve the armhole length.  The wrinkles in this shirt were not loose; in fact they were quite tight on his body.

Just to be sure the problem was not the shoulder slope, I followed the instructions in this video from Threads, and traced around my husband's neck and shoulders to check the slope against the pattern.

Spot on! So if that wasn't the problem, then what was? I continued to do more research on the internet, and came across a post in a sewing forum of someone having a similar problem in fitting a men's t-shirt.  The issue? Atheltic build. More fabric is needed in the upper back and upper chest to accommodate muscles. 

So I traced off the pattern onto tissue paper, and drew lines across the upper chest and back.  Beginning at the center, I cut them open, leaving a hinge at the armhole.  I had my husband try them on carefully, and I let the tissue hang open.  Sure enough, he needed about 1" on the front and 3/4" on the back for the tension in the tissue to be released.

​I don't have pictures of the fitting because he gets antsy and I need to work as quickly as possible. While I try to be professional (even with my spouse) during a fitting, I think he still feels I am negatively judging his shape and not the shape of the pattern.  Something for me to work on, I think.

I had to re-draw the neckline, and also straighten the center back and center front seams.  Time to work on a new muslin!  These fitting issues are making me wonder if it would be worthwhile to develop a men's shirt pattern for athletic builds.  The Sewcialists recently posted an interesting article on sewing for plus-size men.  Sewing patterns for men already seem to be limited, and plus-size even more so.  I already have a long queue of patterns I wish to develop, but I think I will add in a men's shirt for athletic builds in larger sizes. 

Do you sew clothes for men? What sort of fit issues do you have?