Takeoff kinematics of axel jumps were determined from a spatial analysis of singles and doubles performed by 16 figure skaters. The takeoff was divided into glide, transition, and pivot phases. During the glide, horizontal speed remained constant, vertical velocity was slightly negative, and over half the angular momentum for flight was generated. In the transition, skaters gained considerable vertical velocity from tangential motion by rotating about the long axis of the blade, Initially this reduced the angle of the support leg with respect to the vertical while the blade ran in the direction of progression. Most skaters continued to gain vertical velocity by angling the blade to the direction of progression (skidding) and rotating up and forward, still about the blade's long axis. There was little angular momentum gain, and forward speed decreased significantly. In the pivot, skaters rocked forward onto the toe picks losing horizontal speed, vertical velocity, and angular momentum.
Wayne J. Albert and Doris I. Miller
Sam T. Johnson, Grace M. Golden, John A. Mercer, Brent C. Mangus and Mark A. Hoffman
Form skipping has been used to help injured athletes progress to running. Because little research has been done on form-skipping mechanics, its justification as a progression to running exercises is unclear.
To compare ground-reaction forces (GRF) during form skipping and running in healthy subjects at clinically relevant speeds, 1.75 m/s and 3.83 m/s, respectively.
Dependent t tests (α = .05).
Sports-injury research center.
9 male college athletes (age 20 ± 1.33 years, mass 848.4 ± 43.24 N, height 1.80 ± 0.07 m).
Main Outcome Measures:
Average (Fz avg) and maximum (Fz max) vertical GRF and (Fy) braking impulse were compared.
Fz avg and Fz max were greater during running than during form skipping (P < .05). Braking impulses were not different (P > .05).
It appears that Fz, but not the Fy, GRF might explain why form skipping might be an appropriate progression to running.
The kinetic chain is open in the upper extremity skills used in most sports. Although closed chain exercises will increase stability, open chain strengthening is more sport specific. This article addresses general concepts of upper extremity rehabilitation, including exercises to restore normal range of motion, joint mechanics, and muscle strength. The roles of proprioceptive neuromuscular facilitation, plyometric training, and elastic band exercises are also discussed. Finally, a progression of specificity training is presented to return the athlete to successful sport performance.
Douglas R. Keskula
Returning an athlete to functional activity is the primary goal of the sports medicine practitioner. Eccentric exercise may be used throughout the rehabilitation program to improve muscle performance and restore normal function. The selection and progression of eccentric exercise are contingent on treatment goals and the individual's tolerance to activity. Basic concepts of eccentric muscle performance are discussed, and general treatment guidelines with an emphasis on specificity and intensity are presented, to enable the clinician to organize and implement relevant, prudent eccentric exercise within the restrictions of the clinical setting. The use of eccentric exercise in the management of tendinitis is briefly discussed.
Kelly L. Adler, P. Christopher Cook and Brian D. Giordano
Injury to the rectus femoris (RF) myotendinous complex is the most common location of quadriceps injury, due to combined loads of stretch and eccentric muscular activation. To our knowledge, open proximal RF repair has been reported, but a thorough description of postoperative rehabilitation and functional progression of athletic activity has not been described. This case report outlines the rehabilitation of a 30-year-old female following open proximal RF repair after 15 months of failed conservative treatment. Six months postoperatively she returned to competitive recreational soccer with no complaints.
Gail M. Ronchetti, Christopher A. Welch, Brent I. Smith and Danielle E. Blair
A 19-year-old female basketball athlete sustained a right shoulder injury during collegiate competition resulting from a collision causing severe pain and discomfort. The patient was diagnosed with a unique type IV acromioclavicular (AC) separation. Surgical stabilization of the AC joint and slow progression in rehabilitation with immobilization assisted in protecting the reconstruction. Accurate diagnosis and appropriate intervention helped to lead to the successful recovery and return to play for this patient. There are few cases of type IV acromioclavicular separation reported in the literature and none related to basketball. This case presents the challenges related to the diagnosis and rehabilitation following surgical reconstruction of a type IV acromioclavicular separation.
Kristinn I. Heinrichs and Catherine R. Haney
The efficacy of the nonoperative and operative approaches to Achilles tendon rapture has been debated in the literature. In addition, there is little consensus regarding postoperative immobilization with regard to immobilization type, casting position, cast time, and weight-bearing progression. The rehabilitation of the surgically repaired Achilles tendon has not been well described in the literature. The epidemiology and biomechanics of Achilles tendon rupture as well as splint fabrication and rehabilitation protocol for the surgically repaired Achilles tendon in two patients will be presented.
Tishya A.L. Wren and Paul C. Mitiguy
Clinical gait analysis usually describes joint kinematics using Euler angles, which depend on the sequence of rotation. Studies have shown that pelvic obliquity angles from the traditional tilt-obliquity-rotation (TOR) Euler angle sequence can deviate considerably from clinical expectations and have suggested that a rotation-obliquity-tilt (ROT) Euler angle sequence be used instead. We propose a simple alternate approach in which clinical joint angles are defined and exactly calculated in terms of Euler angles from any rotation sequence. Equations were derived to calculate clinical pelvic elevation, progression, and lean angles from TOR and ROT Euler angles. For the ROT Euler angles, obliquity was exactly the same as the clinical elevation angle, rotation was similar to the clinical progression angle, and tilt was similar to the clinical lean angle. Greater differences were observed for TOR. These results support previous findings that ROT is preferable to TOR for calculating pelvic Euler angles for clinical interpretation. However, we suggest that exact clinical angles can and should be obtained through a few extra calculations as demonstrated in this technical note.
Jeff Konin, Michael J. Axe and Ron Courson
The implementation of interval throwing programs during rehabilitation has been suggested in the literature to allow for a quicker and safer return of the throwing athlete to competition. Many programs have clearly focused on baseball players. This program is specifically designed for the football quarterback. The program encompasses a sound flexibility and strength training regime and provides for a supervised step-by-step progression of throwing. Although the authors have found success with early results, practitioners should apply this program with caution, as it may need to be modified for each athlete. The purpose of this paper is to establish a foundation for future work in the area of the throwing shoulder for the football quarterback.
Joaquin A. Barrios, Todd D. Royer and Irene S. Davis
Dynamic knee alignment is speculated to have a stronger relationship to medial knee loading than radiographic alignment. Therefore, we aimed to determine what frontal plane knee kinematic variable correlated most strongly to the knee adduction moment. That variable was then compared with radiographic alignment as a predictor of the knee adduction moment. Therefore, 55 subjects with medial knee OA underwent three-dimensional gait analysis. A subset of 21 subjects also underwent full-limb radiographic assessment for knee alignment. Correlations and regression analyses were performed to assess the relationships between the kinematic, kinetic and radiographic findings. Peak knee adduction angle most strongly correlated to the knee adduction moment of the kinematic variables. In comparison with radiographic alignment, peak knee adduction angle was the stronger predictor. Given that most epidemiological studies on knee OA use radiographic alignment in an attempt to understand progression, these results are meaningful.