KinX Learning Blog
Analysis of the Lat Pulldown Exercise
The lat pull-down is a very effective exercise that is used for developing the upper latissimus dorsi to create "wings." The typical lat pull-down exercise has traditionally utilized a wide pronated grip. Today, however, many bodybuilders also use a narrow grip. When the exercise is done in this manner, different portions of the latissimus are worked together with other secondary muscles. So, for full development of the latissimus and for different stress on the other major muscles involved, it is important that you do both wide grip and narrow grip variants. You can do this by using different bar attachments or by using a lat pulldown machine or bar, with which you can execute both variants. Analysis Because the entire latissimus dorsi is not involved in any one exercise, it is important that you do these two variants to develop this muscle fully. Development of the upper part of the latissimus dorsi will give you wings. Development of the lower part will give you greater definition on the sides of your lower back. However, it is important to have an adjustable seat for proper positioning when you are grasping the bar. Also, the machine should have the different grips, handles or bars to work the muscle completely. The recommendation to pull the bar down in front of the body is relatively recent. For years everyone was told to pull the bar down behind the head until it touched the shoulders. However, most individuals do not have the shoulder joint flexibility needed to do this variant correctly and effectively. As a result they were not getting maximum benefit from this exercise and in some cases were irritating the shoulder joint because of the unaccustomed to extreme backward positioning of the elbows. Some individuals were also bruising the seventh cervical vertebra. Thus it is now recommended to pull down in front which still produces the same, if not better, results. When you are using the wide grip, the exercise may feel easy in the upper range and difficult as the bar approaches your shoulders. If you experience this, it means that you are strong in the initial range of motion and weak in the bottom range. Therefore, when you use machines that do not have variable resistance, especially those with weight stacks, the exercise feels difficult in the early stages and even more so in the bottom position. To counteract this and to strengthen the muscles more effectively in the upper or lower range of motion, you can increase the resistance initially and work only the upper range. Or, you can do the exercise as usual so that it taxes mainly the lower range. When you use the narrow grip, it is important to keep your body erect so that you can more effectively work the lower lat in the upper range of motion. If you lean back, as many people do, you will be working only the lower range of motion. Thus, if you are looking for total development, it is a good idea to do both variants of the exercise with your trunk erect and also with your trunk inclined backward. However, when doing the pull-down with your body inclined backward, be sure to pull the bar down sufficiently so that your elbows go behind your body. You will notice that when you do this, the action is similar to that used in the seated row with a neutral grip. Using a seat with a padded bar that goes over your thighs to hold you down is very important for execution of the lat pull-down. If the bar too secure your body is not available, then you will find your body rising up as you execute the pulldown when you use weights that are close to or greater than your body weight. Also, it is very important that the seat be adjusted so that your arms are maximally extended when you grab the bar. If you have to reach too high for the bar, it will be very difficult to keep your legs secured at the same time. An effective variant of the lat pull-down is the narrow grip pull-down, especially when done with a neutral grip. This version is analogous to the neutral grip pullup. In this exercise you get additional assistance from the posterior deltoid and the long head of the triceps. When you use the wide grip for shoulder adduction, the assisting muscles are the coracobrachialis, subscapularis (when your arm is above the horizontal), short head of the biceps, and long head of the triceps. To execute the lat pull-down successfully, the scapulae must rotate downward as shoulder joint adduction takes place. If the shoulder girdle muscles are not strong enough to rotate the scapulae downward, the arms will not be able to move down and the amount of shoulder adduction or extension is limited considerably. Also, there is a very good chance of injury to the muscles involved.
Major Muscles and Actions Involved in the Lat Pulldown
In the pronated wide grip variant, the upper latissimus dorsi, the teres major, and the lower pectoralis major muscles are involved in shoulder joint adduction. In this action your arms are pulled down in a side (lateral) plane until your upper arm is below shoulder level. In the shoulder girdle, downward rotation of the scapulae is performed by the rhomboid and pectoralis minor muscles. In this action the right scapula rotates clockwise and the left counterclockwise (when viewed from the rear). In the narrow neutral grip variant, the lower latissimus dorsi, the lower pectoralis major, and the teres major are involved in shoulder joint extension. In this action the arms move from in front of the body down to the sides of the trunk. This action is perpendicular to the lateral plane of movement as seen in the wide grip variant. In the shoulder girdle the rhomboid, the pectoralis minor, and the middle trapezius are the major muscles involved in downward rotation and adduction of the scapulae. In this action the muscles pull the scapulae in toward the spine and at the same time rotate the right scapula clockwise and the left counterclockwise when viewed from the rear.
Major Muscles and Actions Involved in the Hanging Leg Raise
Hanging and forearm-supported hanging leg raises involve the iliopsoas, the rectus femoris, and the pectineus in hip flexion and the rectus abdominis and external oblique muscles in spinal flexion. In this action you raise your legs, either held straight or bent, toward your trunk from the vertical position. When your legs get past 45-60 degrees of upward motion, your pelvic girdle begins to rotate posteriorly, that is, your iliac crests move backward and your lower pelvis moves forward and upward to assist in continuing to raise your legs.
Major Muscles and Actions Involved in the Bent-Over Dumbbell Row
The bent-over dumbbell row with both the neutral and pronated grips is a good substitute for the seated row for developing almost all of the back musculature. In this exercise you do not have to contend with the upper body moving forward and back. Variant 1: Neutral grip This variant involves shoulder joint extension, in which the lower pectoralis major, the lower latissimus dorsi, and the teres major participate. The action is assisted by the posterior deltoid. In this action your elbows move from a position in front of your body down and back until they are behind your trunk. Downward rotation and adduction of the scapulae occur in the shoulder girdle when your arms go beyond the level of your back. In this action the lower edges of the scapulae turn inward toward the spine while the upper edges of the scapulae are turned outward on an axis through the center of each scapula when viewed from the rear. As your arms go back past your body, both scapulae move in closer to one another and to the spine. Variant 2: Pronated grip variant In this variant the basic action is different from the neutral grip variant. It involves the posterior deltoid, the teres minor, and the infraspinatus in shoulder joint horizontal extension. In this action your arms travel in a horizontal plane (to the body) from a position in front of your body out to the sides and behind your trunk. In the shoulder girdle the middle trapezius and rhomboid muscles are involved in scapula (shoulder girdle) adduction. In this action the scapulae move from an out-to-the-sides position on the rib cage to close to the spine. In essence, they slide in toward one another and the spine. The arm actions are basically the same as in the neutral grip variant.
Passive and Active Flexibility
Passive flexibility refers to the range of motion (ROM) available when an outside force (i.e., gravity, momentum, another body part or another person) is the causative force. Active (dynamic) flexibility is the ROM produced when muscle force (or gravity) creates the movement range. If the muscles are weak, the ROM will be less than it should be. A passive range of motion shows little correlation to an active ROM. Because you exhibit a great ROM in a static position, it does not mean that it relates to what you do when performing actively. The two are not related! If you desire an active range of motion, you must do active stretching. If you desire a static or passive range of motion, then you should do static stretching. In active stretching, the muscles that are actively involved do so primarily in the eccentric contraction. For example, when you raise your arms overhead as in the lateral arm raise, you are eccentrically stretching the latissimus dorsi and teres major. These muscles undergo an eccentric contraction as you raise the arms to not only control the movement but also to stop the arms from going beyond the capability of the joint. Another example is to lie on your back and then raise one leg as high as possible. Then lower and raise the other leg and repeat in an alternating manner. Every time you raise the leg, you are using the hip flexor muscles to eccentrically stretch the hamstrings and increase the range of motion in every repetition. You can also use gravity as the force to produce active stretching. For example, if you do a good morning exercise keeping the lower back in its normal slightly arched position as you bend over from the hips, you will elicit an eccentric contraction in the hamstrings. Gravity is responsible for pulling the trunk down and the hamstring muscles need the eccentric contraction to control the down movement. When you rise up and each time you go down, you should experience a slightly greater ROM. But you do not force an increase in the range of motion. It happens due to the muscle or gravity pulling. Note that these stretches are more natural since they duplicate what occurs in everyday and sports activities.
Why study the Kinesiology and Biomechanics of Exercise?
Biomechanics and kinesiology are important fields of study for students, educators, and trainers that are interested in exercise science. Here are some pragmatic reasons why. By analyzing the movements that are performed in an exercise biomechanically and kinesiologically, you can you determine which joint actions and muscles play a major role and if the exercise is effective and safe. Characteristics of exercise such as grip, body, and limb position have an impact on muscle involvement, so it is important to understand how they affect the results you will obtain in a training program. Proper technique can help duplicate sports specific movements and improve athletic performance.
Basic Movements in the Wrist Joint
All movements (except rotation) can occur in the wrist joint. This includes adduction (also known as ulna flexion) in which the little finger side of the hand moves toward the body when the arm is in the anatomical position, that is, when the palm faces forward and the hand is alongside the body. Another way to describe this action is to see the little finger side of the hand moving toward the forearm while the hand is kept in line with the forearm. The opposite of adduction is abduction, also known as radial flexion, in which the thumb side of the hand moves away from the body when the arm is in the anatomical position. In this the thumb side of the hand moves toward the forearm while the hand remains in line with the forearm. The wrist can also undergo flexion, in which the palm side of the hand moves toward the forearm. The opposite movement is extension-hyperextension, in which the back of the hand moves toward the posterior surface of the forearm. A combination of all these movements produces circumduction. In this movement, the hand turns around so that the fingers circumscribe a circle and the hand a cone. In many respects the wrist joint is analogous to the ankle joint because it consists of more than one joint with different actions taking place in each joint.
Bicep Curls and the Angle of Muscle Pull
When your arm is straight, the angle of pull of the biceps is very weak. Almost all the force of the flexor muscles is directed to pulling the forearms into the upper arms, and only a small amount of residual force is used for rotating the forearm. However, as the forearm moves closer to the horizontal position, the angle of pull changes dramatically. When the angle of pull is 90 degrees (when your forearm is close to the parallel position), the entire biceps muscle is being used to lift the forearm and the weights. At this time there is no or very little stabilization force (forces that pull into the elbow). Because of this you are much stronger when your arms approach the 90-degree angle, and the weight that seemed heavy when your arms were straight now appears to be quite light. Thus, for maximum development of the muscle through the full range of motion, you should work it in the straight-arm and bent-arm variants.
Torque and Weight Training Exercises
The concept of torque is important in understanding how force is produced in weight training exercises. Its definition is simple: it is the magnitude of twist around an axis of rotation. Thus torque (twist) is rotary (angular) movement in any plane about an axis. Torque is seen in almost all movements of the body as, for example, when you do single joint actions. In isolated movements the axis of rotation is fixed so that the bony lever moves in an arc of a circle. For example, in knee joint extension the foot circumscribes an arc of a circle because it is moving on an angular pathway. When you twist the shoulders they rotate around a stationary vertical axis (for example, the spine), and you make an arc of a circle when viewed from above. When torque is produced, the force is applied at some distance away from the axis of rotation. For example, picture driving a car and turning the steering wheel. The hand applies a force on the wheel (rim) with the axis in the center of the steering column. This is known as an off-center force or, more accurately, an eccentric force. But the rotating or turning force is called torque. It should also be noted that the axis of rotation can also be in motion. This is sometimes needed for safety. For example, in the seated leg extension exercise in which your thigh is immobile, the forces generated in the knee joint are extremely high when you straighten the leg. Because of this, this exercise has been negatively criticized as being potentially dangerous.