Addressing Muscle Atrophy After Surgery
For San Francisco 49ers defensive end Nick Bosa, aesthetic perfection is not a priority. During the team's training camp, observers noted a clear disparity in the size of the 28-year-old athlete's thighs. Bosa openly attributed this to the lingering effects of his October 2025 ACL reconstruction.
"Atrophy is real," Bosa explained to members of the press. He noted that the mandatory rest period following his procedure caused his right leg to lose significant muscle mass compared to his left. He acknowledged that the difference was quite extreme post-surgery and noted that regaining those final few centimeters of muscle could take several years.
Focusing on Athletic Function over Aesthetics
Despite the visible difference, Bosa remains unbothered by the cosmetic aspect of his recovery. He emphasizes that he prioritizes functional performance over building muscle mass for appearances.
"It’s not really a focus for me," Bosa stated. "I’m not going to change my training just to get size. I don’t train like a bodybuilder — I train like an athlete. I’m not going to just add exercises that aren’t good for being an athlete to add size onto my leg." Ultimately, his primary concern is that both legs perform effectively on the field.
Lessons from Previous Rehab
General manager John Lynch has expressed no concerns regarding Bosa’s readiness for the season opener, especially given the defensive end's history with similar injuries. Having torn his ACL previously in September 2020, Bosa successfully returned to form through a combination of intensive rehabilitation and a strict nutritional regimen.
Reflecting on that previous recovery, Bosa admitted he might take a more balanced approach this time around. "I don’t know if I’ll be that strict again," he admitted. "It was just a little over-the-top in terms of cutting out carbs and stuff."
However, one positive constant remains from his last recovery: a feeling of increased speed. "I do feel some similarities to that year, for sure — a little slimmer, lower-body-wise," he added. "And I’m moving really good. So we’ll see if that manifests itself on the field."