Effects of isometric, eccentric, or heavy slow resistance exercises on pain and function in individuals with patellar tendinopathy: A systematic review

Abstract

Background and purpose: The purpose of this study is to evaluate current evidence and provide a review on the effects of isometric, eccentric, or heavy slow resistance (HSR) exercises on pain and function in individuals with patellar tendinopathy (PT).

Methods: Academic journals from CINAHL, Embase, MEDLINE, Scopus, SPORTDiscus™, and The Cochrane Library were searched from inception to August 2017. Screening of reference lists was also performed. Human interventional studies investigating outcomes of pain and function in PT using either isometric, eccentric, or HSR training exercises were included. The McMaster Critical Review Form-Quantitative Studies was used to assess for risk of bias. Levels of evidence were obtained using the National Health and Medical Research Council (NHMRC) evidence hierarchy. The NHMRC Body of Evidence Framework was utilized to formulate recommendations for clinical practice. Extraction of data was performed by two independent reviewers according to predefined data criterion, data were then tabulated, and a descriptive, qualitative data synthesis was performed.

Results: Fifteen studies (3 isometric, 2 HSR, and 10 eccentric) were included for this review. Mean quality score across all studies was 81.6% (range 70% to 93%). Nine studies were of high quality, whereas six studies were of moderate quality. Nine studies were randomized controlled trials, which provided good Level II evidence; four studies were of satisfactory Level III evidence; and two studies were case series (Level IV evidence).

Conclusions: Findings from isometric exercises can be trusted to guide clinical practice (Grade A), whereas eccentric exercises can be trusted to guide clinical practice in most clinical situations (Grade B). It is recommended that HSR exercises should be applied carefully to individual clinical circumstances (Grade C) and interpreted with care. Isometric exercises appear to be more effective during competitive seasons for short-term pain relief, whereas HSR or eccentric exercises are more suitable for long-term pain reduction and improvement in knee function.

Keywords: exercise; pain; patella; tendinopathy.