健身高危动作（from ncsf）

jacky

Contraindicated Exercises

The fitness industry has made significant advancements in using research to improve the biomechanics of lifting and to prevent imbalances by connecting motion segments to optimize coordinated efforts in sports and in life. For knowledgeable exercise professionals the traditional approach of body part isolation using “3 sets of 10” has faded in light of programming for purpose using stress specific exercise techniques. Of interesting however is that with all this new knowledge common biomechanical errors still exist and are performed in fitness centers everyday throughout America.

Likely, some of the most common errors that exist include actions at the shoulders and low back during pulls and presses, knee translation and pelvic instability during hip and knee flexion and excessive recruitment of the hip flexors during abdominal exercises. The usual reasons behind poor lifting technique is exercisers receive incorrect instruction or copy what they see in the gym, or movement compensation occurs due to weakness along the kinetic chain. When force couples fail to exceed the resistive stress along the movement plane other biomechanical actions are used to create momentum to accommodate the movement range of motion.

In many cases these problems can be corrected by a few simple adjustments or adjuncts to the current training program. The first step is to evaluate the problem and identify what is incorrect and why. If it is a simple technique error and muscle strength/balance and flexibility are not contributing factors the correction is easy. Switching the lat pull-down from behind the head to in front is an easy adjustment that improves recruitment while reducing risk of injury. If though, the biomechanics are altered due to musculoskeletal issues, additional strategies must be utilized. Loss of pelvic stability during squatting and leg pressing is a common example of this issue.

Regardless of the problem, there exists a solution and for the most part the first step is focus on the movement efficiency. This means reducing the stress applied during the movement. In most cases this lowering or removing of the weight allows for a better neuromuscular learning environment. Although ego seems to be a very influential factor when it comes to resistance training it is an anchor to the adaptation progress. Exercisers need to understand that it is the quality of the movement that is most influential not the total load moved. For instance, recruiting your back extensors to perform a heavy lat pull-down does not increase recruitment in the intended muscle. Actually, it often reduces it below perceived overload due to changes in localized tension and time under stress, which is counterintuitive. Many people spend many hours in the gym with little return. Exercise without overload is simple a process of heat generation.

The following exercises have been deemed contraindicated as they present more risk than reward. For each exercise a modification exists that reduces the risk for injury while maintaining or increasing the effectiveness of the movement for the desired results. Each includes a problem and a solution. For those movements that cannot be corrected to proper performance remove the exercise from the program and replace it with another more effective activity.

Lat Pull-down behind the Head

Problem: Heightened risk of cervical injury; reduced latissimus dorsi activation.

Correction: Neutral spinal position, depress and adduct scapula pulling the bar to the top of the sternum. Avoid premature arm flexion and changes in hip angle to prevent momentum.

Several research studies have indicated that the pull–up to the front and lat pull-down to the front exceed the latissimus dorsi muscle activation of the behind the head lat pull-down. Additionally, the glenohumaral position is maintained in a more desirable position throughout the exercise.

    Incorrect    Correct

Shoulder Press behind the Head

Problem: Increased risk of glenohumeral injury; potential risk of cervical spine injury

Correction: Standing military press

Research indicates standing pressing activities increase trunk activity and kinetic chain enhancements during pressing exercises more than dumbbell presses seated on the ball.

    Incorrect    Correct

Leg lifts/throws

Problem: Abdominals do not insert on the femur, so the upper leg shouldn’t be moving during the abdominal exercise. Recruitment of the hip flexors pull on the iliac and lumbar spine leading to potential posterior disc compression. Throw downs can also cause abdominal strains and fascial tears.

Correction: Reverse curl-up

A posterior pelvic tilt is requisite to correct exercise performance when the femur presents as the resistance arm. Hip flexion with an anterior pelvic tilt is undesirable as it places limited load on the abdominals and potentially compresses the intervetral discs.

    Incorrect    Correct

Anchored Sit-ups

Problem: Increases hip flexor activity; may cause disc compression; increases risk for low back pain aggravation.

Sit-ups in general are inappropriate for most of the general population due to trunk imbalances and the risk for low back pain. Sit-ups in general heavily recruit the hip flexors. Anchoring one’s feet further increases the hip flexor pull on the hip and spine, further stressing the connective structures. For newer exercisers, curl ups can be used to start but research demonstrates rollout and prone knee flexion on the ball promote more abdominal activation.

Correction: Abdominal curl-ups

Abdominal curl-ups place the majority of the resistive stress in the rectus abdominis. Rollouts also are effective for engaging the trunk musculature without hip flexion.

    Incorrect    Correct

High Angle Upright Row

Problem: Elevated humerus above ninety degrees increases risk of acromion impingement and increases trapezius activation.

Correction: Dumbbell upright row to 90 degrees of humeral abduction or Side Raises to 90 degrees.

The upright row is not a desirable trapezius exercise as humeral abduction is a deltoid movement. Likewise, shoulder elevation and humeral abduction above 90 degrees with inward rotation causes impingement risk.

    Incorrect    Correct

Straight Leg Deadlift

Problem: Pelvis migrates posteriorly; back is rounded placing undue stress on the spinal ligaments and the intervertebral discs; excess range of the hamstrings can also present overstretched induced strain.

Correction: Slight flexion of the knees along with a flat back position places load in the hip extensors and intentionally reduces back activity.

Tight hamstrings and lumbar fascia can cause both rounding of the back and continued knee flexion to attain a greater range of motion. When the pelvis is instable the spine is at risk for injury.

    Incorrect    Correct


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