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- Author: Stephen J Kinzey x
- Athletic Training, Therapy, and Rehabilitation x
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Significance, Statistical or Practical—The Question of so What?
Stephen J. Kinzey
A Comparative Analysis of Selected Ankle Orthoses during Functional Tasks
James A. Yaggie and Stephen J. Kinzey
Context:
Ankle bracing has been used for many years in an attempt to prevent lateral ligamentous injuries of the ankle by restricting joint range of motion (ROM).
Objective:
To examine the influence of ankle bracing on ROM and sport-related performance.
Design:
Repeated measures.
Setting:
Biomechanics laboratory.
Participants:
30 volunteers. None reported ankle trauma within 2 years preceding the study or had other orthopedic conditions that would have affected physical performance.
Intervention:
Three brace conditions (McDavid A101™, Perform-8™ Lateral Stabilizer) were assessed during performance of the vertical jump and shuttle run.
Main Outcome Measures:
shuttle-run time, vertical jump height, inversion, and plantar flexion ROM.
Results:
Both braces restricted plantar flexion and inversion ROM and caused no change in shuttle-run time or vertical jump height.
Conclusions:
Our results indicate that bracing the ankle joint increases external lateral support to the joint without significantly restricting functional ability.
Lower-Extremity-Joint Cryotherapy Does Not Affect Vertical Ground-Reaction Forces during Landing
Andrew G Jameson, Stephen J Kinzey, and Jeffrey S Hallam
Context:
Cryotherapy is commonly used in the care of acute and chronic injuries. It decreases pain, reduces swelling, and causes vasoconstriction of blood vessels. Its detrimental effects on motor activity might predispose physically active individuals to further injury.
Objective:
To examine the effects of cryotherapy on vertical-ground-reaction-force (VGRF) during a 2-legged landing from a 2-legged targeted vertical jump.
Design:
2 × 4 MANOVA with repeated measures.
Setting:
Biomechanics laboratory.
Participants:
10 men, means: 22.40 ± 1.26 years, 76.01 ± 26.95 kg, 182.88 ± 6.88 cm.
Intervention:
VGRF during landing from a targeted vertical jump (90% of maximum) was measured before and after four 20-minute cryotherapy treatments.
Results:
There were no significant differences in VGRF as a result of cryotherapy.
Conclusion:
Under the constraints of this study there is no evidence that returning to activity immediately after cryotherapy predisposes an athlete to injury because of a change in VGRF.
The Effects of Cryotherapy on Ground-Reaction Forces Produced during a Functional Task
Stephen J. Kinzey, Mitchell L. Cordova, Kevin J. Gallen, Jason C. Smith, and Justin B. Moore
Objective:
To determine whether a standard 20-min ice-bath (10°C) immersion of the leg alters vertical ground-reaction-force components during a 1 -legged vertical jump.
Design:
A 1 × 5 factorial repeated-measures model was used.
Setting:
The Applied Biomechanics Laboratory at The University of Mississippi.
Participants:
Fifteen healthy and physically active subjects (age = 22.3 ± 2.1 years, height = 177.3 ± 12.2 cm, mass = 76.3 ± 19.1 kg) participated.
Intervention:
Subjects performed 25 one-legged vertical jumps with their preferred extremity before (5 jumps) and after (20 jumps) a 20-min cold whirlpool to the leg. The 25 jumps were reduced into 5 sets of average trials.
Main Outcome Measures:
Normalized peak and average vertical ground-reaction forces, as well as vertical impulse obtained using an instrumented force platform.
Results:
Immediately after cryotherapy (sets 2 and 3), vertical impulse decreased (P = .01); peak vertical ground-reaction force increased (set 2) but then decreased toward baseline measures (P= .02). Average vertical ground-reaction force remained unchanged (P >.05).
Conclusions:
The authors advocate waiting approximately 15 min before engaging in activities that require the production of weight-bearing explosive strength or power.
Proprioceptive Neuromuscular Facilitation Decreases Muscle Activity during the Stretch Reflex in Selected Posterior Thigh Muscles
Allyson M. Carter, Stephen J. Kinzey, Linda F. Chitwood, and Judith L Cole
Context:
Proprioceptive neuromuscular facilitation (PNF) is commonly used before competition to increase range of motion. It is not known how it changes muscle response to rapid length changes.
Objective:
To determine whether PNF alters hamstring muscle activity during response to rapid elongation.
Design:
2 X 2 factorial.
Setting:
Laboratory.
Participants:
Twenty-four women; means: 167.27 cm, 58.92 kg, 21.42 y, 18.41% body fat, 21.06 kg/m2 BMI.
intervention:
Measurements before and after either rest or PNF were compared.
Main Outcome Measures:
Average muscle activity immediately after a rapid and unexpected stretch, 3 times pretreatment and posttreatment, averaged into 2 pre-and post- measures.
Results:
PNF caused decreased activity in the biceps femoris during response to a sudden stretch (P = .04). No differences were found in semitendinosus activity (P = .35).
Conclusions:
Decreased muscle activity likely results from acute desensitization of the muscle spindle, which might increase risk of muscle and tendon injury.
