A serve clocked at 158 miles per hour draws gasps from a crowd and headlines the next morning, and rightly so. What almost never makes the recap is what that same serve, repeated hundreds of times across a single match and thousands of times across a season, is quietly doing to a shoulder and elbow that were never designed to move quite that fast.

The tennis serve is widely considered one of the most demanding single actions in any racket or throwing sport, and for good reason. During the acceleration phase, the shoulder can rotate internally at angular velocities exceeding 2,500 degrees per second, an extraordinary speed that the joint has to decelerate almost as quickly once the racket makes contact with the ball.

That deceleration phase, not the acceleration everyone celebrates, is where a lot of the real physical cost gets paid. Slowing down a limb moving at that speed places enormous eccentric load on the same shoulder and elbow structures responsible for generating the speed in the first place, and it’s a demand that repeats on every single serve, whether it’s an ace or a routine second serve in the middle of a long rally-heavy match.

A five-set match at a Grand Slam can easily push a player’s serve count into the hundreds once first and second serves are combined across every game. Multiply that across a full tournament run, then across a full season of tournaments, and the raw number of times a shoulder has to generate and then decelerate that much force becomes genuinely staggering, far beyond what most fans watching a single highlight serve ever stop to consider.

Connective tissue absorbs a meaningful share of that repetitive load, more than most players think about when the focus stays on shoulder strength alone. A daily habit built around collagen peptides gives the body raw material for tendon and ligament maintenance, which matters considerably for a player serving hundreds of times across a demanding match and thousands of times across a full season of tournament play. Naked Nutrition markets a grass fed, unflavored version aimed at exactly this kind of steady, unglamorous maintenance rather than a short-term performance spike.

This isn’t about chasing extra miles per hour on the radar gun. It’s about the boring, cumulative maintenance that decides whether a player’s shoulder is still cooperating deep into a five-set match, and deep into a career, rather than becoming the reason that career ends earlier than the talent behind it would have suggested.

The specific risk factors behind serve-related injuries have actually been studied in real depth, not just assumed from how violent the motion looks on slow-motion replay. A 2025 systematic review and meta-analysis published in Advances in Rehabilitation Science and Practice pooled data from 29 studies and identified 130 distinct risk factors associated with serve-related injury, with weekly tennis volume, dominant shoulder rotation strength, and shoulder internal rotation range of motion all showing statistically significant associations with injury risk. Two specific kinetic measures, downward force at the shoulder and inward force at the elbow, showed particularly strong associations with injury among the factors studied.

That finding on weekly volume is the one worth sitting with for any player logging heavy serving reps in practice on top of match play. It suggests the injury risk isn’t just about how hard a player serves in a given match. It’s about the total accumulated volume of serves across practice sessions, matches, and tournaments that a shoulder has to absorb and recover from, week after week, for months at a stretch.

The review also flagged the deceleration phase specifically as a high-risk window, reinforcing that the moment right after contact, when the arm is fighting to slow itself down after generating that much racket-head speed, deserves just as much attention in a strength and conditioning program as the acceleration phase that actually produces the serve speed everyone celebrates.

This kind of finding tends to surprise casual fans more than it surprises anyone who has actually worked with serving athletes, since the visible, celebrated part of the motion, the toss, the load, the explosive swing through contact, is only half the story mechanically. What happens in the fraction of a second immediately afterward is just as demanding on the joint, even though almost none of it shows up in a slow-motion highlight package.

This creates a genuine tension for any player chasing more pace on serve, since the very adaptations that generate a bigger serve, greater shoulder rotation speed and range of motion, are the same adaptations the research associates with elevated injury risk if they aren’t paired with matching strength and recovery work behind the scenes.

The review’s authors noted that seven of the risk factors they identified came from three or more separate studies, which is a meaningfully stronger evidence base than a single isolated finding. Weekly tennis volume, age, body mass, and height all fell into this more robust category, giving coaches a genuinely evidence-backed shortlist of variables worth monitoring rather than just a long list of possibilities with thin supporting data.

Coaches and strength staffs who understand this have started building deceleration-specific strength work directly into a player’s off-court program, rather than only training the muscles that generate racket speed. A shoulder that can produce a huge serve but can’t control the deceleration afterward is carrying risk that a radar gun reading alone will never reveal to anyone watching from the stands.

Age and cumulative years of play showed up as meaningful risk factors too, which lines up with what tour veterans often describe anecdotally: a serve that felt free and easy in their early twenties starts costing noticeably more in recovery time by their late twenties and thirties, even when the mechanics themselves haven’t changed much at all across that stretch of a career.

Recovery tools away from the court matter considerably here too, particularly for players managing a heavy serving workload across a demanding tournament stretch. Heat exposure increases blood flow to fatigued muscle tissue and triggers mild activation of heat shock proteins that support cellular repair, a different mechanism than what stretching alone accomplishes for a shoulder absorbing repeated high-velocity deceleration forces. That specific mechanism is part of why a cedar barrel sauna has found its way into some players’ post-match recovery routines, used as one tool among several rather than a substitute for the strength work that actually protects the joint doing all that work.

None of this means a player should serve more cautiously or sacrifice the weapon that separates the biggest hitters on tour from everyone else. It means the shoulders and elbows generating those record-setting serve speeds need a level of deliberate maintenance that matches the demand being placed on them, since a serve that big is also, by the research’s own measure, a serve that carries real risk if the supporting strength and recovery work isn’t there behind it week after week.

The next time a highlight reel serve lights up a stadium and a headline, it’s worth remembering that the number on the radar gun is only half the story. The other half is everything happening in the weight room and the recovery room that determines whether that same shoulder can keep producing serves like it for years, rather than becoming a cautionary tale about what a big weapon eventually costs the arm generating it match after match.