Affiliations: [a] Department of Sport Science and Kinesiology,
University of Salzburg, Hallein-Salzburg, Austria
Note: [] Corresponding author: Johannes Dirnberger, Department of Sport
Science and Kinesiology, University of Salzburg, 49 Rifer Schlossallee,
Hallein-Salzburg, 5020, Austria. Tel.: +43 0 660 549 4195; Fax: +43 0 662 6389
4881; E-mail: johannes.dirnberger@sbg.ac.at
Abstract: BACKGROUND: Several investigations have reported reproducibility for
isokinetic single-joint (SJ) knee strength measurements. However, to date, only
a few studies have concentrated on multi-joint (MJ) leg strength measurements.
OBJECTIVE: This study is the first to investigate reproducibility
for MJ leg strength measurements using the IsoMed 2000-system, which recently
was introduced into the market. METHODS: Peak Force (PF) of forty-one healthy male subjects (mean
age: 24.4 years) performing concentric and eccentric MJ leg extension at
standardized mean knee-joint angular velocities 40 and 80°/s (i.e.
individual linear foot velocities of 0.12–0.19 and 0.24–0.38 m/s,
respectively) was measured in three identical sessions (T1–T3), separated
by 10–14 days. Repeated measures analysis of variance (ANOVA) was applied
for detection of systematic errors over sessions. Reproducibility was
calculated between consecutive pairs of sessions (T1–T2; T2–T3)
using intra-class correlation coefficients (ICC 2,1) and standard error of
measurement (SEM). RESULTS: Significant increases in mean measurement values of ≈
2–4% from T1 to T2/T3 could be seen for concentric measurements at
40°/s and overall eccentric measurements. Reproducibility calculations
revealed ICC-values of 0.823–0.956 and 0.911–0.978 with
corresponding measures of SEM of 72.1–175.3 and 49.3–125.3 N for
T1–T2 and T2–T3, respectively. CONCLUSIONS: Moderate to high reproducibility was shown for the
IsoMed 2000-system in measuring PF during concentric and eccentric isokinetic
leg extension. However, as data indicate the presence of an initial
practice-based improvement, we recommend the consideration of a familiarisation
session in practice.
Keywords: Reproducibility, practice-based improvement, maximum strength testing, leg press, IsoMed 2000
