Blood flow restriction vs heavy lifting: what the research says.

The 2018 meta-analysis by Lixandrão and colleagues pooled studies that put heavy training directly against low-load BFR and found similar muscle growth from both, regardless of cuff width or pressure. Centner and colleagues found the same in older adults in 2019. A weight at 20 to 40 percent of maximum, lifted under a cuff, grew muscle in the same range as weights at 70 percent and above.

Both meta-analyses found larger strength gains from heavy training. So did the 2017 clinical review by Hughes and colleagues. Strength is partly a skill of the nervous system, learned by producing force against heavy loads, and BFR does not rehearse that in the same way. The one exception was the 2019 NHS trial after ACL surgery, where strength rose 104 percent with BFR and 106 percent with heavy training, with no difference between groups.

When a physiotherapist reaches for BFR, heavy lifting is already ruled out by pain, surgical restrictions or joint damage. The realistic alternative is light exercise without a cuff. Against that, Hughes and colleagues found BFR had a moderate strength advantage across 20 clinical studies (Hedges' g 0.523), and Centner found a large one in older adults. Adding the cuff makes the exercise you can already do worth more.

In the NHS ACL trial, knee pain fell 67 percent with BFR against 39 percent with heavy training, with less swelling and a larger gain in range of motion. In the 2018 knee osteoarthritis trial by Ferraz and colleagues, BFR at 30 percent matched heavy training at 80 percent for strength and muscle, and the paper attributes the difference in pain to exercise-induced knee pain in the heavy group.