Affiliations: [a] Exercise and Sport Sciences Program, University of
Tulsa, Tulsa, OK 74104, USA | [b] Exercise Physiology Laboratory, University of
Nevada-Reno, Reno, NV 89557, USA
Note: [] Address for correspondence: John F. Caruso, Ph.D., 312 Chapman
Hall, 600 S. College Avenue, The University of Tulsa, Tulsa, OK 74104, USA.
Tel.: +1 918 631 2924; Fax: +1 918 631 2068; E-mail: john-caruso@utulsa.edu
Abstract: Volunteers provided data comparing two classes (integrated
electromyography, anthropometry) of predictor variables to explain the variance
associated with calf press performance done against inertial resistance.
Subjects performed three 3-set 10-repetition workouts, each starting with body
mass and body surface area determinations. During the first and last
repetitions per set, integrated electromyography (IEMG) was collected from the
lateral and medial gastrocnemius (LG, MG), and soleus (SOL). Multivariate
regression revealed all prediction equations were significant (p < 0.05). For
tenth repetition dependent variables, anthropometry explained more variance
than did IEMG; perhaps due to greater series elastic element involvement of the
musculotendinous unit, less motor unit recruitment may have occurred. IEMG was
generally more correlated to first than tenth repetition dependent variables.
Among IEMG variables, SOL data explained more variance seen with tenth
repetition concentric variables; yet correlations between dependent measures
and MG data were usually high for first repetition eccentric, but low for tenth
repetition, variables. The diverse levels of variance explained among
independent variable classes illustrate pronounced differences in what they
contribute to performance, and within IEMG variables suggests considerable
anatomical/histochemical differences among the triceps surae.
