Muscle Activation Patterns using The Carving Pro
Maastricht University:
Pieter Oomen (MSc)
Hans Savelberg (PhD)
December, 2010
Introduction
The Carving Pro is a full lateral movement. Various Carving Fitness exercise positions are assumed to
condition numerous muscle groups differently. The purpose of this study is to determine which
muscle groups are involved by the Carving Fitness movement, at what point in the cyclical movement
each group is activated, and whether or not the different exercise positions involve the various
muscle groups differently.
When muscles are stimulated by nerves to deliver power, a weak electrical current is sent to the
muscle cells. The size of the electrical current depends on the amount of muscle mass stimulated,
and is thereby a measure of the muscle force required. This electrical activity can be measured using
electromyography (EMG), a technique that gathers data from electrodes placed on the skin. EMG
was used in this study to identify and differentiate muscle groups involved in the Carving Fitness
movement by the Carving Pro user.
The questions to be answered were:
o
Which muscles are active at any given moment during the full lateral movement cycle on
the Carving Pro?
o
What, if any, is the impact of the various Carving Fitness exercise positions on muscle
group activation?
Method
Using surface electrodes, the muscle activity of four healthy male subjects was measured while they
used the Carving Pro in five different exercise positions.
Twelve different muscle groups in the upper body, upper legs, and lower legs were targeted for
measurement. Surface electrodes to measure these groups were applied following strict Surface
Electromyography for the Non-Invasive Assessment of Muscles (SENIAM) protocol. Data from these
electrodes was collected by a Programmable Ambulant Signal AcQuisition (PASAQ) platform and
stored in a PC for offline analysis.
Activation patterns of the following muscle groups were measured. (Please see Appendix 1 for
associated muscle functions.):
gluteus maximus
gluteus medius
multifidus
obliquus externus
vastus medialis
rectus femoris
tensor fascia latae
biceps femoris
gracilis
soleus
gastrocnemius medialis
tibialis anterior
In addition, a reference electrode was placed on the tuberositas tibiae.
Each test subject was familiarized with the Carving Pro prior to the measurement and given training
on the five exercise positions (please see Appendix 2). After familiarization, electrodes were
positioned, applied, and connected to the PASAQ system. Each subject was then directed to perform
the Carving Fitness movement for one minute from each of the five exercise positions. Motion
frequency and intensity from one exercise position to the next were kept the same.
The Carving Fitness movement is a reciprocating movement, alternately engaging the right, then the
left leg, much like a “skater’s hop.” Measurements of muscle activity in exercise position 1 (the
default position) were used as a baseline. Measurements taken from the other four exercise
positions were compared to this baseline.
A threshold of 60% was used as the threshold for muscle activation. “Muscle activated” was
operationally defined as the time during which that muscle’s EMG activity exceeded this 60%
threshold of ambient electrical current, while EMG time below this threshold was defined as “muscle
not activated.” By comparing the maximum EMG values during the movement cycle of the different
exercise positions, muscle activation patterns and loading differentials could be evaluated.
Results
Appendix 3 presents muscle activation pattern examples. The left-hand column shows activation
patterns for the movement from left to right; the right-hand column for movement right to left.
In spite of individual differences in activation patterns across the four test subjects, the data allow
several conclusions to be drawn.
In exercise position 1, the highest number of muscles are active approximately 40% into the
movement cycle (80% of the time bar in the left-hand column), just before the right leg reaches the
final position. Approximately halfway through the return movement depicted in the right-hand
column (about 80% into the full cycle), most muscles are disengaged.
Exercise positions 3, 4, and 5 show longer activation patterns; muscle groups are re-engaged sooner
and remain active longer.
Several muscle groups in exercise positions 2, 3, 4 and 5 are more active than in exercise position 1
(please see Table 1).
•
In exercise position 2, three of the four test subjects experienced more biceps femoris,
gluteus maximus, and gluteus medius engagement than in exercise position 1.
•
In exercise position 3, for three of the four test subjects, maximum multifidus activity
increased.
•
In exercise position 4, for all test subjects, the activity of the tensor fascia latae, rectus
femoris, multifidus and gluteus maximus was greater than in position 1.
•
For three of the four subjects, the tibialis anterior, biceps femoris and gluteus medius
muscles experienced higher activity in positions 2, 3, and 4 than in position 1.
•
In exercise position 5, for all test subjects, the gracilis, biceps femoris, tensor fascia latae,
multifidus and gluteus maximus were more active than in position 1.
•
For three of the four subjects, EMG values of the rectus femoris were also higher in position 5
than in position 1.
Table 1
The following table shows by how many subjects a certain muscle was more active in exercise
positions 2, 3, 4, and 5 than in the exercise position 1.
tibialis anterior
gastrocnemius medialis
soleus
gracilis
biceps femoris
tensor fascia latae
rectus femorus
vastus medialis
obliquus externus
multifidus
gluteus medius
gluteus maximus
Total
Position 2 Position 3 Position 4 Position 5
2
2
3
3
1
0
2
1
1
2
2
1
1
2
2
4
3
2
3
4
1
2
4
4
2
2
4
3
1
1
2
1
1
1
1
2
2
3
4
4
3
1
3
2
3
2
4
4
21
20
34
33
Discussion and Conclusions
The purpose of this study was to determine select muscle activation patterns during the Carving
Fitness movement, how long those muscles remained activated, and whether different Carving
Fitness exercise positions taxed the muscle groups differently.
The Carving Pro seems to use all the examined muscles and therefore train them.The Carving Pro
engaged all of the leg muscles measured (calf, thigh, and buttocks).
In the fourth and fifth “hands free” exercise positions, the leg muscles were loaded more heavily than
in the other conditions. The multifidus, a dorsal muscle, also seemed more engaged in exercise
positions 4 and 5.
The legs are also more taxed in the squat positions (exercise positions two and three) than in exercise
position 1.
Appendix 1: Muscle Location and Function
m. tibialis anterior
Function: dorsal flexion
of foot at ankle, inverts
foot
m. tensor fascia latea
Function: hip abduction,
knee stabilization, used
in walking
m. gastrocnemius
medialis
m. soleus
m. gracilis
Function: plantar flexion
Function: thigh
adductor, bends the hip
and knee joint
Function: plantar flexion
m. rectus femoris part of
quadriceps
m. vastus medialis
behind rectus femoris
Function: extends leg at
knee
m. biceps femoris part of
the hamstrings
Function: extends thigh
at hip, flexes leg at knee,
laterally rotates leg
when knee flexed)
m. obliques externus
m. multifidus
m. gluteus maximus
Function: rotation
Function: lateral flexion
& rotation. Extension,
hyper- extension of
spine.
Function: extension and
lateral rotation of hip at
thigh, assists in thigh
abduction.
m. gluteus medius
Function: Thigh
abduction at hip, medial
and lateral rotation of
thigh
Appendix 2: Different Exercise Positions on the Carving Pro
1. Hands high on the handlebar,
leaning forward
2. Knees bent, lean forward with
hands low on the handlebars
3. Leaning backwards, knees
bent in squat position
4. Hands on the back, requires
superior coordination.
5. Hands free. Upper body
rotates while arms turn
across upper body
Appendix 3: Results – (Muscle Pattern Examples)