Isometric Core Resistance Training Volume does not Predict Functional Outcomes in Workers' Compensation Lumbar Fusion Patients

Core training is considered a key component of low back rehabilitation. This study assessed whether isometric core resistance training volume (IM vol ) could predict functional outcome (Physical Demand Level; PDL) following a sports performance based rehabilitation program in workers' compensation lumbar fusion patients (n=38). IM vol was calculated in bodyweight equivalents * time (BWeq * sec) as previously described. PDL was measured at program completion (KEY Method) and classified by occasional occupational lifting requirements: LIGHT (L; 20lbs), LIGHT‐MEDIUM (LM; 35lbs), MEDIUM (M; 50 lbs), MEDIUM‐HEAVY (MH; 75lbs), HEAVY (H; 100lbs), VERY HEAVY (VH; >100lbs). ANOVA analyzed relationships between PDL and IM vol Paired t‐test assessed pre/post change. Alpha=0.05. Data are mean±SEM. PDLs were LM=3, M=4, MH=10, H=6, VH=15. For analysis the L/LM, M/MH, and H/VH groups were pooled. First week IM vol were: L/LM 199±55 BWeq*sec; M/MH 156±17 BWeq; H/VH 145±11 BWeq. IM vol increased during the program in all groups. Peak IM vol were: L/LM 300±35 BWeq*sec; M/MH 355±28 BWeq*sec; H/VH 336±27 BWeq*sec. No differences existed between groups at either time point. Linear regression yielded a correlation coefficient of R 2 =0.0053 for the relationship between IM vol and PDL. These results suggest that IM vol does not predict PDL following a rehabilitation program.