european college of sport science

08:30 - 10:00
Oral presentations
OP-ST09 Sports 9
OP-ST09 Sports 9
MUSCLES OF BODY BUILDERS ARE INTRINSICALLY STRONGER THAN THOSE OF ACTIVE UNTRAINED CONTROLS
NARICI, M.V., SEYNNES, O.R., KAMANDULIS, S., SKURVIDAS, A., BRAZAITIS, M., KAIRAITIS, R., RITTWEGER, J., ERSKINE, R.,
MAGANARIS, C.N.
1. MANCHESTER METROPOLITAN UNIVERSITY, MANCHESTER, UNITED KINGDOM, 2. LITHUANIAN ACADEMY OF PHYSICAL EDUCATION,
KAUNAS, LITHUANIA
The massive muscle hypertrophy displayed by body builders (BB) is expected to be matched by a proportionate increase in muscle force.
However, a higher specific tension of type 2A and type 2X single fibres of the vastus lateralis muscle of professional BB, compared to
non-training controls (CTRL), has been found (1). The present study investigated whether the greater single fibre intrinsic force was reflected
by a higher force per cross-sectional (F/CSA) of the whole muscle, once accounting for differences in neural activation, muscle
architecture and moment arms. Eight professional male BB (aged 29.4±5.5 years, height 177.9±4.1 cm, body mass 91.7±13.4 kg), recruited
by the Lithuanian Academy of Physical Education, were compared to 12 untrained, male CTRL (aged 20.8±2.5 years, height
177.4±4.6 cm, body mass 74.8±5.6 kg). Maximum isometric torque of the knee extensors (KE) was measured by isokinetic dynamometry
at 60, 70, 80, 90 deg of knee extension. Quadriceps tendon (QT) moment arm (ma) was estimated by anthropometry (2) and KE volume
(Vol) was estimated from a regression between anthropometric thigh muscle plus bone Vol and MRI KE Vol (3). Fascicle length (Lf) and
pennation angle of the vasti lateralis (VL), medialis (VM), intermedius (VI) and rectus femoris (RF) were measured by ultrasound at rest and
at the optimum angle of KE maximum torque. KE maximum force (F) was calculated as: KE torque at the optimum angle/QTma. Physiological
cross-sectional area (PCSA) of VL, VI, VM and RF was calculated as the ratio of Vol/Lf, enabling KE F/PCSA to be estimated. BB KE
force, Vol and PCSA were respectively, 52.3% (P