Research Shorts

Hamstring strains have a 20 to 33% reinjury rate. That number has barely moved in decades despite decades of research and rehabilitation advancement. The reason might be simpler than anyone wants to admit — most rehab programs never actually train the hamstring where it gets injured. Sprinting tears hamstrings at long muscle lengths, under high eccentric load, with the hip flexed and the knee exte...

Two groups. Same exercise. Same total training load. The only difference was how fast they lowered the bar. Six weeks later the results told a clear story. The fast eccentric group increased rate of force development by up to 19% and grew muscle fascicle length by 10%. The slow eccentric group got stronger and added muscle thickness — but their explosive power actually decreased. CMJ power dropped...

Three months of hard training. Squats, leg press, knee extensions. Strength went up 18%. Muscle size increased 10%. Then the athletes stopped everything for three months. Strength returned to baseline. Muscle mass disappeared. And then something nobody expected — unloaded movement speed jumped 14% and power increased 44%. Not despite the detraining. Because of it. The mechanism is a molecular one....

Seven studies. 201 athletes. Five databases screened. This is what a meta-analysis looks like when the data actually tells a clean story. Flywheel resistance training outperformed traditional weight training on change of direction performance with a standardized mean difference of 0.64. That might sound small. It isn't. The within-group effect for flywheel training came in at 1.63 — a large effect...

Science just proved something coaches have ignored for years. You can build serious strength and still run slower. A 9-week study showed athletes getting stronger week after week while their sprint times got worse. Then one thing changed. This is the training mistake killing athletic performance.

Hamstring injuries are the most common and costly injury in professional soccer — and they're getting worse. But not all hamstring injuries are equal. The T-junction, where the long and short heads of the biceps femoris meet distally, represents one of the most poorly understood and potentially most dangerous subtypes — with re-injury rates as high as 54%. Research from an English Premier League c...

Plyometrics are everywhere. Every gym program, every pre-season block, every speed development plan has them. But there's a catch most coaches never mention — the tendon adaptation everyone is chasing doesn't show up in weeks. It takes years. Four years of tracking elite jumpers revealed that tendon stiffness — a key marker of injury resilience and force transfer — only meaningfully increases with...

Coaches have been programming training for decades based on heart rate zones, GPS data, and how hard athletes say they feel. There's just one problem. None of those metrics actually tell you what's happening inside the muscle itself. A new case report by Martin Buchheit and Paul Laursen just changed that. Using a portable electrical stimulation device called Myocene, researchers measured something...

What if the most sophisticated athletic training tool in the world was something you've been doing since you were five years old? A group of researchers in France just published a study that should make every strength and conditioning coach stop and pay attention. They strapped 16 athletes to force plates sampling at 2000 times per second and made them do everything — drop jumps, hurdle jumps, ank...

Coaches have been arguing about it for decades. Should athletes train on one leg or two? Is the Bulgarian split squat superior to the back squat? Do unilateral exercises build more muscle because they isolate the target muscle better? A meta-analysis finally dug into the data — and the answer is more nuanced than either camp wants to admit. For muscle growth, it doesn't matter. Bilateral or unilat...

Every sports scientist uses the countermovement jump. It's fast, it's simple, and coaches love it. There's just one problem — jump height might be the least useful number it produces. This episode breaks down why elite football clubs are going deeper into the force-time curve of the CMJ and finding signals that jump height completely masks. An athlete can land the same height week after week while...

Most fitness tests have a fatal flaw — athletes can game them. Sprint a little harder, push through pain, fake the effort. But your heart rate? It doesn't lie. In this episode, we break down how elite sports scientists at PSG, the AFL, Bundesliga, and rugby clubs worldwide quietly replaced expensive, exhausting fitness tests with a simple 4-minute jog — and how a single number from a heart rate mo...

For decades, coaches have been splitting training into "aerobic" and "anaerobic" work like they're two separate things. Turns out the reality is way more interesting. After analyzing 102 studies, researchers pinpointed the exact moment your body switches from being primarily anaerobic to primarily aerobic during all-out exercise — and it's 78.6 seconds. That single number has massive implications...

This research paper examines the use of low-frequency fatigue (LFF) monitoring as a tool for managing the return-to-play process in elite football players. By utilizing electrical stimulation and force measurements, practitioners can objectively assess contractile impairment without requiring maximal effort from the athlete. The text details a four-case series involving injuries such as ACL recons...

The Reactive Strength Index (RSI = jump height ÷ contact time) is the standard field metric for assessing the stretch–shortening cycle (SSC) — the store-and-release elastic energy mechanism behind explosive movement. But RSI has real problems: it mixes incompatible units (producing m/s despite being treated as dimensionless), it ignores drop height entirely, and it rewards very short contact times...

Not all reps are created equal — and this study proves it. Researchers assigned 45 adolescent male sprinters to one of three velocity-based training (VBT) programs, each using a different velocity loss threshold (10%, 20%, or 30%) during back squat training over six weeks. While all groups got stronger, athletes training with the lowest threshold consistently outperformed their peers in sprint spe...

For over a decade, force-velocity profiling (FVP) has been the gold standard for sprint assessment—a supposedly elegant way to identify whether athletes are "force-dominant" or "velocity-dominant" and prescribe individualized training accordingly. Coaches swear by it. Scientists publish papers validating it. But in 2023, biomechanists dropped a bombshell: FVP is a "dead end"—mathematically sophist...

Elite alpine skiers are crashing their knees constantly—and here's the problem: even after surgery, nobody really knows when they're ready to race again. A new study just cracked the code using machine learning and a simple jump test. Researchers analyzed 836 countermovement jumps from 24 ACL-reconstructed ski racers versus 42 healthy controls and trained AI models to predict injury status with 89...

Your smartwatch is watching your heart—literally. A dive into a massive new study analyzing 2 million nights of sleep data from 21,000+ people wearing the WHOOP strap, and the findings are wild. Researchers discovered that a hidden metric called HRV-CV (heart rate variability coefficient of variation) is basically a snitch for your lifestyle choices. Higher alcohol consumption? Your heart rate var...

Forget $50K wearable systems. We found a machine learning model that predicts athletic injuries with 98% accuracy using just workload and recovery data. In this episode, we explore how Random Forest AI and explainable machine learning (SHAP) can tell coaches exactly which athletes are at risk—and why. The crazy part? It works on basic spreadsheet data that colleges already have. We break down the...

What if the secret to preventing injuries in young soccer players wasn't expensive wearables or cutting-edge technology—but a 15-minute warm-up routine? We dive into a massive meta-analysis of 19 studies covering 28,200 youth soccer players to uncover what actually works. From the FIFA 11+ program to simple neuromuscular training, we break down why some injury prevention programs reduce injuries b...

Researchers compared three groups of elite soccer players over six weeks: those doing standard soccer training only, those adding Nordic hamstring exercises twice weekly, and those adding comprehensive sprint training twice weekly. The results revealed a critical gap. Sprint training produced moderate increases in hamstring fascicle length—16% gains—compared to just 7% with Nordic exercises. But h...

Most coaches rely on daily readiness scores to make training decisions—but the research shows they're getting incomplete data. In this episode, we break down why your readiness metrics are only telling part of the story, and introduce the multidimensional monitoring framework elite teams use to actually track training effects. Learn which metrics matter, how to interpret them correctly, and the de...

Most coaches train hamstrings the traditional way—short muscle length, minimal hip flexion. But sprinters reach maximum stretch at 70+ degrees of hip flexion during the late swing phase, where injuries actually happen. This study revealed something simple but powerful: train at the position where injury occurs, and your muscles adapt to prevent it. Athletes trained at long muscle length produced n...

Coaches misunderstand velocity-based training. They think it's a way to train. It's a way to measure if training works. Research proves the load-velocity relationship is 95% predictable. That's mechanical law. You can't create independent training effects with arbitrary velocity splits—the physics won't allow it. When you increase force production, velocity increases everywhere. Light loads get fa...