Fat is dead weight. Muscle is functional. Fat would slow you down alot more than muscle. If your training is still sport specific then you will maintain or increase your speed. Look at sprinters their all muscle. He doesn't look juiced he looks like he added a bit of muscle but is also a little softer. I'd be more worried about his stamina than his speed. Standing up to a bigger stronger man plus being bigger yourself will have an impact on stamina. Imo he hasn't had enough time to grow into and get used to his new weight. Let alone get used to being walked down by a guy whose bigger and stronger. Sent from my XT1563 using Tapatalk