Biomedical Engineering Reference
In-Depth Information
useful as research and development tool. Examples of the iFES-LCE being used for
research include the testing of biomechanical model for FES-evoked cycling (Sin-
clair 2001; Sinclair, 2004) and physiological response during FES-evoked cycling
(Theisen, 2002).
Isokinetic exercise has long been recognised as a type of exercise whereby
the muscle gains strength evenly throughout its range of movement, and is the
fastest way to increase muscle strength. By definition, isokinetic exercise involves
“an external means of holding the speed of body movements to a constant rate
irrespective of the magnitude of forces generated by the participating muscles”
(Hislop, 1967). Isokinetic exercise has been found to be an efficient, adaptable and
reliable method of exercise (Grooten, 2002), thus most suitable in muscle strength
building by individuals with SCI.
7.5.4 Isokinetic Cadence Control
Isokinetic motorized FES cycling systems have the advantage that cadence control
is not reliant upon muscle stimulation. Non-motorized FES cycle ergometers rely
upon the muscle stimulation to maintain the pedalling cadence. Relying on muscle
stimulation to control pedalling cadence restricts the stimulation patterns that can
be employed.
The mechanism of cadence control (i.e. motorized isokinetic vs. flywheel-
braked isotonic FES-evoked cycling) at between 35-50 rev
min 1 made no no-
ticeable difference to the muscle powers generated or metabolic responses elicited
(Fornusek, 2005).
Examples of stimulation intensity control schemes or modes that an isokinetic
FES cycle can easily employ are manual control, a preset protocol, feedback
control of power output, interval training, low cadence training, and eccentric
training. Manual and preset protocol control of stimulation intensity is possible
because the cycling motion does not rely on the muscle stimulation intensity; this
is particularly useful for subjects who are very sensitive to muscle stimulation.
Interval training has shown great potential to enhance the intensity of FES cycling
(Janssen, 1996). Low cadence and eccentric training (Fornusek, 2009) may enhance
the peripheral benefits of FES cycling.
The iFES-LCE is able to offer high-resistance low-cadence FES cycling. Mus-
cle fatigue rates are less at lower pedal cadences (15 rev
·
min 1
during FES-
evoked cycling and can produce higher muscle forces during FES-cycle training
(Fornusek, 2004). Training with greater muscle forces has produced improved
strength (Belanger, 2000; Hartkopp, 2003; Crameri, 2004) and hypertrophic gains
(Dudley, 1999). Therefore, FES-LCE training at slow pedal cadences may confer
improved strength and hypertrophic gains compared to higher pedal cadences
(35-50 rev
·
)
min 1
. Although the pedalling cadence affects the power output,
it does not appear to influence the potency of cardiovascular stress (Fornusek,
2008). Therefore, low cadence training should be as effective as higher cadences
for cardiovascular fitness training.
·
)
 
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