Letters to the Editor-in-Chief of JOSPT as follows:

• "Manual Magic: The Method Is Not the Trick" and Authors' Response
• "Moving Past Sleight of Hand" and Authors' Response
• "Core Muscle Activation During Swiss Ball and Traditional Abdominal Exercises" and Authors' Response

J Orthop Sports Phys Ther 2010;40(8):535-541. doi:10.2519/jospt.2010.0201

STUDY DESIGN: Controlled laboratory study using a repeated-measures, counterbalanced design. OBJECTIVES: To test the ability of 8 Swiss ball exercises (roll-out, pike, knee-up, skier, hip extension right, hip extension left, decline push-up, and sitting march right) and 2 traditional abdominal exercises (crunch and bent-knee sit-up) on activating core (lumbopelvic hip complex) musculature. BACKGROUND: Numerous Swiss ball abdominal exercises are employed for core muscle strengthening during training and rehabilitation, but there are minimal data to substantiate the ability of these exercises to recruit core muscles. It is also unknown how core muscle recruitment in many of these Swiss ball exercises compares to core muscle recruitment in traditional abdominal exercises such as the crunch and bent-knee sit-up. METHODS: A convenience sample of 18 subjects performed 5 repetitions for each exercise. Electromyographic (EMG) data were recorded on the right side for upper and lower rectus abdominis, external and internal oblique, latissimus dorsi, lumbar paraspinals, and rectus femoris, and then normalized using maximum voluntary isometric contractions (MVICs). RESULTS: EMG signals during the roll-out and pike exercises for the upper rectus abdominis (63% and 46% MVIC, respectively), lower rectus abdominis (53% and 55% MVIC, respectively), external oblique (46% and 84% MVIC, respectively), and internal oblique (46% and 56% MVIC, respectively) were significantly greater compared to most other exercises, where EMG signals ranged between 7% to 53% MVIC for the upper rectus abdominis, 7% to 44% MVIC for the lower rectus abdominis, 14% to 73% MVIC for the external oblique, and 16% to 47% MVIC for the internal oblique. The lowest EMG signals were consistently found in the sitting march right exercise. Latissimus dorsi EMG signals were greatest in the pike, knee-up, skier, hip extension right and left, and decline push-up (17%-25% MVIC), and least with the sitting march right, crunch, and bent-knee sit-up exercises (7%-8% MVIC). Rectus femoris EMG signal was greatest with the hip extension left exercise (35% MVIC), and least with the crunch, roll-out, hip extension right, and decline push-up exercises (6%-10% MVIC). Lumbar paraspinal EMG signal was relative low (less than 10% MVIC) for all exercises. CONCLUSIONS: The roll-out and pike were the most effective exercises in activating upper and lower rectus abdominis, external and internal obliques, and latissimus dorsi muscles, while minimizing lumbar paraspinals and rectus femoris activity.

J Orthop Sports Phys Ther 2010;40(5):265-276, Epub 22 April 2010. doi:10.2519/jospt.2010.3073

KEY WORDS: crunch, EMG, low back pain, lumbar spine, rectus abdominis, sit-up

Presented at the Interim Conference of the American Orthopaedic Society for Sports Medicine, February 8, 1980, Atlanta, GA.

Address correspondence to: Lonnie Paulos, MD, 2350 Auburn Ave., Cincinnati, OH 45219.

The purpose of this paper is to present the specifics and rationale of our postoperative rehabilitation program after anterior cruciate ligament (ACL) reconstruction and compare it with an international survey of 50 knee experts. It is important to stress that what we present is opinion. This opinion, however, is based on principles, guidelines, and specifics which we believe are important.

The early phases of our program are based upon time and control of forces, both of which are necessary for ligament healing. The classic parameters of return to play do not indicate healing of ligament tissue and must not be substituted for time restraints.

After ACL repair and reconstruction, there are five phases of rehabilitation: maximum protection (12 weeks), moderate protection (24 weeks), minimum protection (48 weeks), return to activity (60 weeks), and activity and maintenance.

The maximum protection phase consists of the early healing period and controlled motion period. The early healing period is governed by a principle which requires the absolute control of forces to prevent disruption of the suture line or attachment site. This time will vary according to the surgical technique. We do not allow motion during this period. During the controlled motion period, we allow motion but control external forces to protect ligament healing.

The moderate protection phase consists of the crutch-weaning and walking periods. The major goal of the moderate protection phase is to prepare the patient for walking. The principles which govern Phase 2 are that walking activities create large anterior cruciate ligament forces and healing strength is still low. A balance of quadriceps and hamstring forces is necessary for proper knee kinematics. De-emphasis of quadriceps exercises and emphasis of hamstring muscles is appropriate; however, both muscle groups must be strengthened. The crutch-weaning period is designed to allow the gradual increase of motion and strength to sustain walking activities.

A paradox of exercise exists for strength building. To push weight from 30° of flexion into full extension will protect the patellofemoral joint but will create large forces on the ACL. Our compromise is to push low weight through a full range of motion. We begin full weightbearing no sooner than the 16th week.

The final three phases of our program are designed to develop dynamic stability through strength, coordination, and endurance. Phase 3, the maximum protection phase, consists of the protected activity period from the 24th through the 36th week, and the light activity period from the 37th through the 48th week. Restrictions include no running, no jumping, and the use of a brace full-time. The light activity period allows further time to protect the slow healer. This may be shortened or lengthened, depending upon the patient's condition and goals.

Phase 4, the return to activity phase, begins nine to 12 months after surgery. It consists of the advanced rehabilitation period and the running period. The advanced rehabilitation period is designed to achieve maximum strength and further enhance neuromuscular coordination and endurance. The running period begins when the operated leg has at least 75 percent of the strength and power of the normal leg.

The activity and maintenance phase consists of the return to sport and maintenance periods. On return to sport, the patient must gradually resume full activity by advancing from skill drills. The maintenance program consists of triweekly strength-building sessions, brace protection during sporting, and avoidance of high-risk activities.

J Orthop Sports Phys Ther 1991; 13(2):60-70.