A student once remarked, "You only say it because you teach it."
I replied, "No, Ma’am, that is WHY I teach it!"
Let me explain.
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Roger, teaching Step Aerobics,
at Bally’s Total Fitness,
North Hills location, Pittsburgh, PA
Step Aerobics involves the four major physiological tenets of fitness-motion enhancement:
- I. SYNCHRONOUS AEROBIC/ANAEROBIC MOTION
- In step aerobics, you are combining an anaerobic exercise (lifting your entire body weight against gravity) while moving in an aerobic state (continuous and steady).
- NOTE: The primary movers (muscles) are the body’s largest
and strongest,
- which maximizes the caloric expenditure for the time spent.
- II. MUSCULATURE ENHANCEMENT
- During exercise, the body can generate energy from its muscle mass under three conditions:
- Primary Muscles
The joint(s) muscle(s) directly involved in the exercise.
- Synergistic Muscles
Assist and support the primary movers
- Stabilizing (balancing) Muscles
Can include 90 percent of the body’s musculature.
- Primary Muscles
-
NOTE: Free movement of Step Aerobics uses all
three muscle energy
- conditions. This results in more calories expended for the amount of time spent.
- III. PLANES OF MOVEMENT
- Our bodies move in several planes of motion: Sagittal (forward and backward), lateral (right side, left side), transverse (up, down), linear (whole body movement), rotational and diagonal.
-
NOTE: Step Aerobics utilizes all planes of movement.
- IV. PROPRIOCEPTION AWARENESS
- The proprioceptive sense (body’s computer) enables us to recognize the location, direction and rate of movement
of one body part in relation to the other body parts (neuromuscular pathways).
- NOTE: Negotiating an obstacle (the step) using all planes of movement
- will highly enhance this mind/body connection.
COMMENTARY
- NOTE: A professional cyclist puts more wear and tear on the knee joint
- in one year of training than most fitness enthusiasts do in their lifetime.
- In Step Aerobics, the three most common Improper Use Movements are:
- 1. Fractional knee and hip extension
2. Knee joint over rotation
3. Incomplete quadriceps stretch
- NOTE: Bouncing and jumping off the step with a tight calf muscle
- can cause lower leg problems.
KNEE JOINT PHYSIOLOGY
Knee joint motion from the sagittal plane includes flexion and extension.
- FLEXION: Decreasing the angle (bent knee) between the two bones
- (femur and tibia).
- EXTENSION: Increasing the angle (to straight leg) between the two bones
- (femur and tibia).
The knee extensors (lifters) belong to the muscle group of the quadriceps (the strongest muscle group of the body).
It is a composite muscle that includes four distinct parts (rectus femoris, vastus lateralis, vastus intermedius and vastus medialis). All four muscles extend the leg at the knee joint and function as a unit.
1. Vastus Lateralis
2. Vastus Intermedius
3. Vastus Medialis
4. Rectus FemorisQuadriceps These four muscles insert (attach) via the patella (kneecap) tendon, to the proximal (upper) tibia (shin bone). Three of the four (vastus group) originate (attach) to the proximal (top) femur (upper leg bone). The other muscle (rectus femoris) originates to the hip bone (iliac spine) making it the only two-joint muscle of the group. The difference in skeletal attachment between the vastus group (the three single joint muscles) and rectus femoris (two joint muscle) demands special attention to proper form.
PROPER FORM
Step up on the bench and lift your body straight up to FULL KNEE EXTENSION (straight leg).
- Caution: Do not over-extend (lock) the knee joint. Ensure the
- upper body maintains FULL HIP EXTENSION (standing tall).
EXAMPLE:
Imagine you are balancing a book on top of your head as you are stepping up on the bench. Keep your upper body centered and balanced on your hips. Your lower back (lumbar) should be tension free. Your shoulders are loose and your neck is relaxed. Your mind is clear. Your thoughts are focused on moving your body in your space.
HOW TO CORRECT IMPROPER USE MOVEMENTS
- 1. FULL KNEE EXTENSION
- The vastus medialis (main knee stabilizer) is not fully emphasized (engaged)
until the last 20 degrees of knee extension (straight leg).
The synergistic action of this muscle group (quadriceps) warrants a full range of movement (straight leg) during the step-up phase. Not doing so can create an imbalance-of-action in this muscle group. This can result in potential knee problems.
- CAUTION: Do not over-extend by locking the knee joint.
- 1a. FULL HIP EXTENSION
- When the hip joint is in the state of flexion (bent) while the knee joint is moving to extension (straight leg), the rectus femoris (two joint muscle) becomes less effective as an extensor (lifting muscle) of the knee joint. The work is being done primarily by the three vasti muscles which creates a functional imbalance.
NOTE: A muscle’s ability to exert force decreases as it shortens.
- 2. MINIMAL KNEE JOINT ROTATION
- The knee joint is mainly a one plane of movement (sagittal) joint (forward or backward). The knee joint is also capable of some rotational movement (30 degrees internal and 40 degrees external).
It is usually less because of inflexibility.
To ensure you are not over-rotating,
keep the foot and knee in line (under 20 degrees) with your hip.
- CAUTION: Minimize rotation forces placed on the knee joint.
- Do not turn your body past the rotational ability of your knees while your foot is planted.
- 3. COMPLETE QUADRICEPS STRETCH
- A quadriceps stretch should be with the knee in maximal flexion (bent knee) while bringing the hip to maximal unstressed extension.
NOTE: By not fully extending the hip joint, the rectus femoris- (two-joint quadriceps muscle) realizes less than full extensibility (stretch). This leads to an asymmetrical tension pull on the patella (kneecap) by having flexible vastus muscles but a tight rectus femoris muscle.