In response to the comment on the article "Which instruments can detect submaximal physical and functional capacity in patients with chronic nonspecific back pain?

(1)

Spine www.spinejournal.com 529

L

ETTERS

DOI: 10.1097/BRS.0000000000000189

The manuscript submitted does not contain information about medical device(s)/drug(s).

No funds were received in support of this work.

No relevant fi nancial activities outside the submitted work.

IN RESPONSE:

W

e thank Dr. Almosnino for critically reading and dis-cussing our systematic review. 1_{However, his} argu-ments are based on the assumption that research concerning this topic should be based on 2 criteria: whether or not the patient is performing sincerely, and whether the effort is representative for the patient’s maximal capacity. Dr. Almos-nino does not, however, explain the (theoretical) basis for this distinction. We specifi cally stated in our introduction that we did not distinguish between reasons for submaximal capacity, because our study focused on the identifi cation of submaximal capacity, regardless of its origin. Identifi cation of the reason for submaximal capacity is a different issue that requires a differ-ent study methodology, as Dr. Almosnino correctly points out. There are several factors that can infl uence the level of capac-ity, 2_{and these factors are diffi cult to objectify. Also, we worked} with a defi nition of submaximal capacity because effort and capacity can be interpreted in different ways. We found strong evidence that submaximal capacity can be detected in patients with chronic low back pain with a lumbar motion monitor or visual observations accompanying a functional capacity evalu-ation lifting test. We did not fi nd evidence for the detection of maximal capacity and for other instruments.

Suzan van der Meer, MSc Department of Research Methodology, Measurement and

Data Analysis, University Twente, Enschede, the Netherlands

Maurizio Trippolini, MSc Department of Rehabilitation Medicine, Center for

Rehabilitation, University Medical Center Groningen, the Netherlands, and Department of Work Rehabilitation, Rehaklinik Bellikon, SUVA Care, Bellikon, Switzerland

Job van der Palen, PhD Department of Research Methodology, Measurement and

Data Analysis, University Twente, Enschede, the Netherlands, and Department of Epidemiology, Medisch Spectrum Twente, Enschede, the Netherlands

Jan Verhoeven, MSc Condite, Disability Management, Enschede,

the Netherlands

Michiel Reneman, PhD Department of Rehabilitation Medicine, Center for

Rehabilitation, University Medical Center Groningen, the Netherlands

References

1. van der Meer S , Trippolini MA , van der Palen J , et al. Which instru-ments can detect submaximal physical and functional capacity in patients with chronic nonspecifi c back pain? A systematic review . Spine (Phila Pa 1976) 2013 ; 38 : E1608 – 15 .

2. Robinson ME , Dannecker EA . Critical issues in the use of mus-cle testing for the determination of sincerity of effort . Clin J Pain 2004 ; 20 : 392 – 8 .

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