Summary of an article analyzing acute and chronic workloads and their relation to injuries in elite rugby league players.
28 male elite rugby league players aged 24.8 (±3.4) (Australia).
Observation over two Australian National Rugby League (NRL) seasons. One club.
injury (“any time-loss injury that resulted in a player being unable to complete full training, or missing match time” recorded by senior physiotherapist)
between-match recovery time: short (<7 days) or long (7 days or more)
workload (GPS): total distance [m]
acute workload (1 week workload), chronic workload (previous 4-week average of weekly workloads), ACWR (Acute:chronic workload ratio)
ACWR – Acute:chronic workload ratio = a ratio of traning load acummulated over the recent week and the training load accumulated over the previous 4 weeks
In two seasons there were 44 match injuries and 9 training injuries. No difference in risk for match injury was following short versus long recovery time.
For short between-match recovery times, the risk of injury was the lowest for high between-match workload.
During short between-match recovery:
players were at 2.88 times higher risk of match injury when they ACWR was high (1.23-1.61), than when ACWR it was moderate-high.
the risk of match injury for ACWR very-high (≥1.62) was 5.8 times higher than for moderate-high ACWR and 3.41 times higher than for low ACWR.
As the chronic workload increased, the risk of sustaining subsequent match injury decreased lineary.
For long between-match recovery times, the risk of match injury for very-high ACWR (≥1.50) was 4.46 times higher than for moderate-high ACWR.
Take home message
Hulin BT, Gabbett TJ, Caputi P, Lawson DW, Sampson JA. Low chronic workload and the acute: chronic workload ratio are more predictive of injury than between-match recovery time: a two-season prospective cohort study in elite rugby league players. Br J Sports Med. 2016 Aug 1;50(16):1008-12.