A 2024 study published in Sports Health examined 99 publicly available interval throwing programs designed to help baseball players return from injury or build arm strength during the off-season. Researchers Boos and colleagues evaluated these programs on methodological quality, evidence-based criteria, and practical completeness. What they found should concern every coach, athletic trainer, and athlete who has ever downloaded a throwing program from the internet or followed a generic protocol handed out at a clinic. The programs demonstrated major inconsistencies, systematic omissions, and a near-total lack of evidence-based guidance. Fifty-four percent were intended for injured athletes returning to throwing, yet 42 percent offered no timeline for completion, 63 percent lacked structured guidance for setbacks, and only 20 percent referenced any peer-reviewed evidence, most of which was outdated by over a decade. These aren't minor oversights, they're fundamental gaps that leave athletes vulnerable to reinjury, prolonged recovery, and compounded tissue damage.

What the Study Found

The researchers analyzed 99 programs obtained from public sources including hospital websites, sports medicine clinics, university athletic departments, and professional organizations. They evaluated each program across multiple dimensions, target population, initiation criteria, progression parameters, completion timeline, setback management guidance, warm-up protocols, arm care recommendations, and citation of supporting evidence.

Only 60 percent of programs specified any formal criteria for initiating throwing. Pain absence was the most common criterion when mentioned, but even that was inconsistently defined. Some programs required complete pain resolution, others allowed mild discomfort, and many didn't specify at all. Without clear initiation criteria, athletes are left guessing whether they're ready to start, which means some begin too early when tissues haven't healed adequately, while others delay unnecessarily and lose conditioning.

Throwing progression parameters varied wildly with no apparent rationale. Minimum throwing distances ranged from 20 feet in some programs to 45 feet in others. Maximum distances ranged from 90 feet to 250 feet. Some programs progressed in 15-foot increments, others in 30-foot jumps. The number of throws prescribed at each distance ranged from 10 to 50. There was no consistency in whether intensity, distance, or volume drove the progression, and most programs didn't explain the logic behind their structure. This means an athlete following one program might be throwing twice as much volume at half the distance compared to another program, with both claiming to be appropriate for the same injury.

Forty-two percent of programs provided no timeline for completion. Eight percent offered specific return-to-competition timelines, but the rest left athletes in limbo about how long the process should take. Without a timeline, there's no way to gauge whether progress is appropriate or whether the athlete is advancing too quickly or too slowly. It also makes it impossible to coordinate the throwing program with other aspects of rehabilitation like strength training, mobility work, or sport-specific conditioning.

Sixty-three percent of programs lacked structured guidance for managing setbacks or symptom flares. This is particularly problematic because setbacks are common during return-to-throw progressions. Tissues don't heal linearly, and introducing load after a period of rest frequently produces temporary inflammation or discomfort that resolves with appropriate management. But without guidance on when to back off, when to modify, and when to seek medical attention, athletes either push through symptoms that indicate real problems or panic at normal recovery responses and shut down unnecessarily.

Thirty-two percent of programs provided no formal warm-up recommendations. Sixty-three percent offered no arm care guidance beyond the throwing itself, no strength work, no mobility exercises, no recovery protocols. This is akin to telling someone to run a marathon but not giving them any advice on training, nutrition, or pacing, just the route map. Throwing is the stimulus, but everything surrounding the throwing, preparation, strength maintenance, tissue recovery, determines whether that stimulus produces adaptation or breakdown.

Only 20 percent of programs cited any peer-reviewed evidence, and when evidence was cited, it was typically studies published more than a decade ago. The field of throwing biomechanics, workload monitoring, and rehabilitation has advanced considerably in the past 10 years, but most of these programs haven't been updated to reflect current understanding.

Why This Information Is Important

To be honest, this reminds me of every athlete who followed a program religiously and still had a setback three weeks in. They're confused and frustrated, convinced they did something wrong. But the program itself was fundamentally flawed, not because distances or volumes were wrong, but because it had no mechanism to account for individual response, no way to adjust based on how the body was handling load, and no objective criteria for determining appropriate progression.

The absence of objective assessment is the most critical failure. Research shows that when pitchers throw at 75 percent perceived effort, they only reduce elbow torque by 7 percent and velocity by 11 percent. At 50 percent perceived effort, they still generate 86 percent of maximum torque and 78 percent of maximum velocity. Athletes are reliable in repeating perceived efforts but systematically miscalibrated. What feels like half effort is actually near-maximum stress. Programs prescribing "light toss" or "60 percent effort" without objective measurement leave athletes thinking they're conservative while actually loading tissues at intensities that may exceed healing tolerance.

Generic programs can't account for mechanical maladaptations from injury or surgery. When athletes compensate for pain or alter delivery to avoid discomfort, they retrain their nervous system differently. That pattern doesn't automatically disappear when pain resolves or structure heals. Without mechanical assessment and correction, athletes return to throwing with inefficient patterns that create abnormal stress. The program might progress beautifully from 45 to 180 feet, but with compromised mechanics, they're reinforcing dysfunction at progressively higher intensities.

Return to performance research illustrates real consequences of inadequate protocols. Tracking 129 MLB pitchers post-UCL surgery found 82 percent returned to play by year three, but only 28 percent achieved full performance. Command recovered in 89 percent, but velocity, workload capacity, and value lagged significantly. Generic programs treating clearance as a finish line rather than starting point contribute to this gap.

Individual variability in workload response is another factor generic programs miss. Professional pitchers generate more velocity with less relative elbow torque using greater trunk and pelvis rotation, while high school pitchers rely more on the arm. The same throwing volume creates different stress profiles depending on mechanical efficiency. Research on adolescent pitcher fatigue shows hip strength and coordination decline after just 35 pitches, meaning capacity changes within a single session. Programs prescribing fixed volumes can't account for this fatigue-related degradation.

How Can This Information Be Applied

If you're following an interval throwing program, recognize it's a framework, not a prescription. It provides structure but can't account for individual response, mechanical changes during time off, or whether prescribed workload matches current tissue capacity. You need monitoring systems and adjustment protocols.

Use objective measures whenever possible. Track velocity with radar guns during sessions. If velocity drops significantly mid-session, you're approaching workload capacity limits. If velocity doesn't return to baseline between sessions, reduce frequency or volume. Even simple tracking like soreness scales, sleep quality, and warm-up duration provide useful feedback about appropriate dosing.

Build in formal reassessment points. Don't progress just because the calendar says so. After each phase, reassess range of motion, strength, and mechanics. If shoulder external rotation has decreased, tissues are tightening in response to load and progression needs to slow. If grip or rotator cuff strength hasn't returned to baseline, increasing throwing volume creates compensatory stress elsewhere.

Have predetermined setback management rules. If soreness exceeds a threshold, back off to previous volume. If pain occurs during throwing, stop and get evaluated. If velocity drops by a certain percentage, take extra rest. Having these rules prevents ignoring warning signs or overreacting to normal responses.

Integrate arm care and strength work as essential components, not optional add-ons. Shoulder strength, scapular stability, rotator cuff endurance, and grip strength determine how well the arm tolerates throwing stimulus. Research shows these physical qualities influence elbow stress for a given velocity. Addressing only throwing without supporting physical qualities builds on an inadequate foundation.

Work with professionals who can assess mechanics and identify compensations, particularly after injury or surgery when movement patterns have changed. Identifying issues like early trunk rotation, inadequate hip drive, altered arm slot, or timing disruptions early is far easier than correcting them after hundreds of reinforcing repetitions.

Understand timelines are guidelines, not guarantees. If you're not hitting objective benchmarks by the expected week, don't force progression to meet arbitrary deadlines. If you're exceeding expectations, accelerate cautiously with continued monitoring. The goal isn't completing the program on schedule, it's building sustainable throwing capacity.

Conclusion

The finding that 99 publicly available interval throwing programs demonstrate major inconsistencies, omissions, and lack of evidence-based guidance reveals a systemic problem in how we approach return-to-throw progressions. Forty-two percent provide no completion timeline, 63 percent lack setback management guidance, and only 20 percent cite any evidence, most of which is outdated. Throwing parameters vary wildly with no clear rationale, and most programs offer no warm-up or arm care recommendations beyond the throwing itself.

Supporting research shows why these gaps matter. Athletes can't accurately self-assess throwing effort, what feels like 50 percent is actually 86 percent of maximum stress. Return to play after UCL surgery doesn't equal return to performance, with only 28 percent of pitchers achieving full metrics by year three despite 82 percent returning to competition. Generic programs can't account for mechanical compensations, individual variability in workload tolerance, or differences in kinetic chain efficiency. Without objective monitoring and individualized adjustment, athletes are essentially guessing their way through rehabilitation.

The application is clear. Throwing programs are frameworks, not prescriptions. Athletes and coaches need systems for objective assessment, formal reassessment points, predetermined setback management strategies, and integration of strength and arm care work. Timelines are guidelines that must bend to individual response, not arbitrary deadlines to be met regardless of readiness. The goal isn't completing the program, it's building an athlete who can sustain competitive demands without breaking down. That requires continuous assessment, responsive adjustment, and recognition that rehabilitation is a dynamic process that can't be captured in a static template.

References

1. Boos AM, Sambare N, Smith MV, Freehill MT, Bowman EN, Erickson BJ, Chalmers PN, Sciascia A, Camp CL. Interval Throwing Programs for Baseball Players: Methodological Assessment of the Quality and Construct of Publicly Available Programs. Sports Health. 2024;16(3):428-437.
   
   
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3. Mastroianni MA, Kunes JA, El-Najjar DB, Obana KK, Desai SS, Morrissette CR, Alexander FJ, Rondon AJ, Trofa DP, Popkin CA, Levine WN, Ahmad CS. Return to Performance After Ulnar Collateral Ligament Surgery in Major League Baseball Pitchers. Am J Sports Med. 2025;53(1):137-144.
   
   
4. Aguinaldo AL, Escamilla RF. Role of Rotational Kinematics in Minimizing Elbow Varus Torques for Professional Versus High School Pitchers. J Appl Biomech. 2019;35(1):8-16.
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