Running is associated with intervertebral disc adaptations: a pre-planned secondary analysis of the ASTEROID randomised controlled trial.

PURPOSE: To identify patient and intervention factors that moderate the effects of running on intervertebral disc health (IVD) in adults with non‑specific chronic low back pain.

METHODS

Pre‑planned secondary analysis of a 12-week parallel-group (1:1) randomised controlled trial of 40 adults with non-specific CLBP (mean [SD] age: 33 [6] years, female: 50%). Participants were allocated to a digitally-delivered progressive run-walk interval exercise training program (3 days/week, 30 min/session) or waitlist control. Magnetic resonance imaging at baseline, six, and 12 weeks quantified primary outcome IVD composition as whole-disc T2 (ms) from T11/T12 to L5/S1. Moderators included baseline degeneration (Pfirrmann grade; aggregated Pfirrmann score), sex, body mass index, and intervention factors (cumulative running volume, mean speed, and dominant surface). Linear mixed models were fitted at the IVD level to estimate group-by-time effects within each moderator-defined subgroup (α = 0.05).

RESULTS

The highest aggregated Pfirrmann scores reflecting greater multi-level degeneration (estimated marginal mean net difference [95%CI]: 3.42 [0.22, 6.62] ms, P = 0.036), cumulative running volumes between 28.6 and 46.1 kms (4.80 [2.51, 7.10] ms, P < 0.001), mean running speeds between 10.5 and 11.7 km/h (2.46 [0.14, 4.79] ms, P = 0.038), and running on grass (2.93 [0.10, 5.76] ms, P = 0.043) positively moderated between-group IVD T2 changes.

CONCLUSION

In this pre-planned secondary analysis of a randomised control trial of a run-walk program, our data suggest running speed, volume and surface, as well as more multi-level IVD degeneration, may be associated with more favourable 12-week IVD T2 changes. Findings are hypothesis-generating and may inform future trials designed to optimise IVD health.