Sc. Swanson et Ge. Caldwell, An integrated biomechanical analysis of high speed incline and level treadmill running, MED SCI SPT, 32(6), 2000, pp. 1146-1155
Purpose: Recent sprint training regimens have used high-speed incline tread
mill running to provide enhanced loading of muscles responsible fur increas
ing forward running speed. The goal of this study was to document the joint
kinematics, EMG, and swing-phase kinetics of incline treadmill running at
4.5 m . s(-1) with a 30% grade, and compare these data to that of level run
ning under similar conditions. Methods: Sagittal plane video (200 Hz) and E
MG from eight lower extremity muscles were recorded during each of three lo
comotion conditions: incline running at 4.5 m . s(-1) and 30% grade (INC),
level running at 4.5 m . s(-1) (LSS), and level running at the same stride
frequency as INC (LSSF). A rigid body model was used to estimate net muscle
power and work values at the hip, knee, and ankle during swing. Timing and
amplitude of EMG signals for each muscle relative to footstrike were compa
red between conditions. Results: Stride frequency and percentage of stride
spent in stance were significantly higher during INC (1.78 Hz; 32.8%) than
in the LSS (1.39 Hz; 28.8%) condition. Stride frequency played an important
role, as most measures were more similar between INC and LSSF. Extensor ra
nge of motion of all joints during push-off was higher for INC. During INC,
average EMG amplitude of the gastrocnemius, soleus, rectus femoris, vastus
lateralis, and gluteus maximus were higher during stance, whereas the hams
trings activity amplitudes were lower. Average power and energy generated d
uring hip flexion and extension in the swing phase were greatest during INC
. Conclusions: These data suggest that compared with LSSF and LSS, INC prov
ides enhanced muscular loading of key mono- and bi-articular muscles during
both swing and stance phases.