Mechanical properties, safety and resistance values of Lemgruber® elastic tubing

Abstract

Background: Lemgruber® elastic tubing has been used as an adjunct to exercise training with positive effects in healthy adults and in patients with chronic lung disease. Despite its benefits, there is a lack of information on the specific resistance, elongation, reproducibility and safety of the different types of Lemgruber® elastic tubing. Objectives: The primary outcome was to assess the length-resistance relation (E/R) of five Lemgruber® elastic tubing of different diameters. Secondary outcomes included the development of reference equations of resistance according to elongation of Lemgruber® elastic tubing types and; the description of Lemgruber® elastic tubing safety and; the description of elongation of Lemgruber® elastic tubing using a clinically useful outcome (i.e. range of motion, in degrees). Methods: The relation between elongation and resistance of Lemgruber® elastic tubing was investigated in a laboratory environment. Secondly, reference equations for the resistance according to the elongation in each Lemgruber® elastic tubing were calculated. Finally, the elongation of the tubing during movements in different degrees of range of motion were estimated using mathematical models, so that the resistance provided by the tubing for any exercise could be predicted. Results: Lemgruber® elastic tubing provided a large array of resistance varying from 3 ± 0.1 Newtons (N) to 537 ± 13 N (mean ± standard deviation). The maximal resistance deemed safe for each of the five Lemgruber® elastic tubing were: 173 ± 25 N, 280 ± 23 N, 409 ± 40 N, 395 ± 37 N and 537 ± 13 N. Reference equations had nearly perfect predictive power (r2 = 0.99) for all polynomial non-linear models (p < 0.001 for all). Conclusions: Lemgruber elastic tubing progressively increased resistance with increased elongation. The large array of resistances delivered by Lemgruber® elastic tubing, along with its safety and good estimation of reference values, support its use in clinical practice.