# ACL, Hamstrings and Concussion: Sports Research

> Seven sports medicine studies on ACL rehab vs surgery, sprinting for hamstrings, tendinopathy, ACL prevention, concussion, BFR and rotator cuff pain.

URL: https://physioai.in/blog/sports-medicine-research-roundup-acl-hamstrings

Published: 2026-10-09 · Research roundup · PhysioAI

This roundup summarises seven sports medicine studies relevant to physiotherapists: ACL management and prevention, hamstring training, patellar tendinopathy, concussion, blood-flow restriction training and rotator cuff-related shoulder pain. Across them, progressive loading and early, structured activity did more than gadgets or rest.

## Key takeaways

- A 2025 meta-analysis found no higher return-to-sport rate after ACL reconstruction than with supervised rehabilitation alone, though the evidence is low certainty.
- Neuromuscular warm-ups of about 10 minutes twice a week cut ACL injuries in female athletes by 61%.
- Light exercise within two days of a concussion was linked to faster symptom recovery in college athletes.
- Real blood-flow restriction gave no advantage over a sham cuff during ACL rehabilitation.
- Sprinting and Nordic hamstring exercises produced similar hamstring adaptations.

## ACL reconstruction vs rehabilitation alone

A 2025 systematic review and meta-analysis compared ACL reconstruction with supervised, exercise-based rehabilitation alone. Across 15 studies, reconstruction was not associated with higher return-to-sport rates: 48% returned to their pre-injury sport after reconstruction and 45% after rehabilitation alone. Activity levels were also similar. The authors rate the evidence as low certainty and note that many studies carried a risk of bias in favour of surgery.

**What it means in the clinic:** the belief that every athlete needs surgery to play again is not well supported. Structured rehabilitation is a legitimate first-line option to discuss with ACL patients, alongside surgical opinion and the athlete's goals.

*Source: Filbay et al., Sports Medicine 2025 (PMID 40603829).*

## Sprinting builds hamstrings as well as Nordics

In this trial, 38 collegiate athletes completed seven weeks of lower-limb training with either added Nordic hamstring exercises or added sprinting. All groups improved biceps femoris muscle architecture and eccentric hamstring strength.

**What it means in the clinic:** compliance with Nordic exercises is often poor in sport. Planned, progressive sprint exposure offers another route to similar protective adaptations, and the two can be combined.

*Source: Ripley et al., PLOS ONE 2023 (PMID 36862645).*

## Heavy slow resistance plus ultrasound for patellar tendinopathy

A randomised trial of 51 athletes with patellar tendinopathy compared eight weeks of heavy slow resistance (HSR) training plus high-dose ultrasound, HSR alone, or ultrasound alone. All groups improved. The combined group gained the most on the VISA-P score (21 points), compared with 17 points for HSR alone and 6 points for ultrasound alone. At 16 weeks, the two lifting groups kept improving, while the ultrasound-only group slipped back.

**What it means in the clinic:** the loading effect lasted. A passive modality may add to exercise in the short term, but it did not replace it.

*Source: Xiao et al., BMC Sports Science, Medicine and Rehabilitation 2024 (PMID 39390552).*

## A 10-minute warm-up for ACL prevention

The FAIR consensus review pooled 82 studies and 154,561 participants. Neuromuscular training (balance, strength, agility and change-of-direction work) done for at least 10 minutes twice a week reduced ACL injuries in female athletes by 61%, rated as high-certainty evidence, and ankle sprains by 39%.

**What it means in the clinic:** prevention is the cheapest ACL treatment. Team physiotherapists can build this into existing warm-ups without extra sessions.

*Source: Bullock et al., British Journal of Sports Medicine 2025 (PMID 40645751).*

## Early light exercise after concussion

This study followed 1,228 college athletes across 30 institutions in the NCAA-DoD CARE Consortium. Starting light exercise within two days of concussion was associated with a 92% greater likelihood of symptom recovery and a median recovery that was 2.4 days shorter. Waiting eight or more days to start exercise was linked to slower recovery.

**What it means in the clinic:** strict rest in a dark room is outdated. Early, symptom-guided light activity belongs in concussion care. Because this was an observational study, it shows an association, not proof of cause.

*Source: Lempke et al., Sports Medicine 2023 (PMID 37209368).*

## Blood-flow restriction after ACL surgery vs a sham cuff

In a double-blind, placebo-controlled trial, 48 athletes did low-load training with either real blood-flow restriction (BFR) or a sham cuff. Training ran for one month before ACL surgery and four to five months after it. There was no difference between groups in quadriceps strength, muscle size, muscle physiology or knee mechanics.

**What it means in the clinic:** in this trial the cuff added nothing. The authors suggest clinicians weigh BFR's cost, time and discomfort against these results. Progressive loading did the work in both groups.

*Source: Erickson et al., Medicine and Science in Sports and Exercise 2025 (PMID 39350350).*

## Motor control exercise for rotator cuff-related shoulder pain

A meta-analysis in the Journal of Orthopaedic and Sports Physical Therapy pooled 22 randomised trials with 1,281 patients with rotator cuff-related shoulder pain. Motor control exercise programs reduced disability more than non-specific exercise in the short and medium term. They did not significantly outperform non-specific exercise for short-term pain.

**What it means in the clinic:** motor control work is probably slightly better, not a magic program. The authors note that the benefit may come from progression and tailoring, features every good shoulder program should already have.

*Source: Lafrance et al., Journal of Orthopaedic and Sports Physical Therapy 2024 (PMID 38848304).*

## The pattern across these studies

Rehabilitation alone matched surgery for return to sport. A short warm-up prevented a large share of ACL tears. A BFR cuff added nothing over sham, and concussed athletes who moved early recovered faster. The consistent message for sports physiotherapists is less reliance on devices and rest, and more planned, progressive loading.

## Follow sports research with PhysioAI

PhysioAI's [Advances feed and Review of Literature](https://physioai.in/research) let you follow new sports and musculoskeletal research, filter by evidence type, save papers, and turn a clinical question into a screened, cited summary built from real papers. Use it to orient yourself, then read the key studies in full.

## The Instagram post

This article is also a 9-image Instagram carousel by PhysioAI:

1. 01 Cover (https://physioai.in/blog/sports-medicine-research-roundup-acl-hamstrings/01.webp)
2. ACL surgery vs rehab alone: no difference in return to sport (https://physioai.in/blog/sports-medicine-research-roundup-acl-hamstrings/02.webp)
3. Sprinting builds hamstrings as well as Nordics (https://physioai.in/blog/sports-medicine-research-roundup-acl-hamstrings/03.webp)
4. Heavy slow lifting + ultrasound gave the biggest jumper’s knee gains (https://physioai.in/blog/sports-medicine-research-roundup-acl-hamstrings/04.webp)
5. A 10-minute warm-up cut ACL tears in female athletes by 61% (https://physioai.in/blog/sports-medicine-research-roundup-acl-hamstrings/05.webp)
6. Exercising within 2 days of concussion: 92% likelier recovery (https://physioai.in/blog/sports-medicine-research-roundup-acl-hamstrings/06.webp)
7. Blood-flow restriction after ACL surgery: no better than a sham cuff (https://physioai.in/blog/sports-medicine-research-roundup-acl-hamstrings/07.webp)
8. Rotator cuff pain: motor control edged out generic exercise (https://physioai.in/blog/sports-medicine-research-roundup-acl-hamstrings/08.webp)
9. 09 PhysioAI's take (https://physioai.in/blog/sports-medicine-research-roundup-acl-hamstrings/09.webp)