| 1. |
- Antonopoulos (Kvist), Joanna, et al.
(författare)
-
Anterior tibial translation related to isokinetic concentric quadriceps torques
- 1996
-
Ingår i: Isokinetics and exercise science. - 0959-3020 .- 1878-5913. ; 6:2, s. 145-151
-
Tidskriftsartikel (refereegranskat)abstract
- Sagittal translation of the tibia was examined in a static test with 90 N force at 20°of knee flexion and dynamically during knee extension in a Biodex machine using increasing quadriceps torque in six healthy volunteers. The translation increased in a non-linear fashion with increasing torque. Similar relative increases in quadriceps torque caused similar relative increases in translation in the different individuals. The dynamic translation at the individual maximum quadriceps torque was equal to the static 90-N translation. There was a negative correlation between the maximum quadriceps torque and the static 90-N translation. The results indicate that the quadriceps torque is related to the amount of translation in the knee joint possibly by some feed back mechanism from the ligaments preventing abnormal translation. The findings also imply that a limitation of quadriceps torque around 80% of maximum would limit the strain in an injured ligament to a level not higher than what is caused by normal laxity measurements.
|
|
| 2. |
|
|
| 3. |
- Gillquist, Jan
(författare)
-
Clinical experience versus scientific evaluation : A biased opinion?
- 2002
-
Ingår i: Sports medicine and arthroscopy review. - 1062-8592 .- 1538-1951. ; 10:3, s. 178-182
-
Tidskriftsartikel (refereegranskat)abstract
- We present the characteristics. of the scientific method and examine its effect on clinical facts. Because the scientific technique involves both reduction of facts (details) and generalization, it results in dangerous deformations of the clinical situation. Statistical methods used indiscriminately, as in many contemporary scientific papers, result in many false alarms and invalid therapies. Because of these limitations, the scientific method is not suitable for analysis of the true therapeutic situation, but can be used to gather biologic background facts necessary for the interpretation of observations made in the therapeutic situation. It is pointed out that clinical:experience is an ability to listen and observe that goes beyond science.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Kvist, Joanna, 1967-, et al.
(författare)
-
Anterior positioning of tibia during motion after anterior cruciate ligament injury
- 2001
-
Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 33:7, s. 1063-1072
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The purpose of this study was to describe the sagittal tibial translation and EMG activity of muscles v. medialis and lateralis, gastrocnemius, and hamstrings, during common locomotion, in patients with an anterior cruciate ligament deficiency (ACL-def) and uninjured controls.METHODS: In 12 ACL-def patients and 17 controls, sagittal tibial translation was registered with the CA-4000 electrogoniometer during level walking, cutting, and stair walking. Tibial position at each flexion angle was expressed relative to the femuro-tibial position at passive knee extension. EMG activity, measured with ME-4000, was normalized to the individual maximum isometric voluntary contraction for each muscle.RESULTS: During the weight-bearing phase of motion, the tibia was anteriorly positioned in all legs. In the injured leg, the tibia translated more rapidly to an anterior position that was maintained for a longer time during the gait cycle. In the noninjured knees, motions with increased load lead to an increased anterior tibial translation in contrast to the injured knees, where the maximum displacement was already reached during level walking. The quadriceps and gastrocnemius muscles were simultaneously active during stance phase. Hamstrings were mainly active when the knee was close to extension and translation increased in spite of this activity.CONCLUSIONS: The mechanism of the anterior positioning of tibia is qualitatively similar in the normal and the injured knee, but that position is obtained much further forward in the ACL deficient knee. Quadriceps and gastrocnemius muscles seem to work synergistically to stabilize the knee by maintaining the anterior position of tibia during weight-bearing motion. The role of hamstrings to restrict anterior translation is questioned.
|
|
| 7. |
- Kvist, Joanna, 1967-, et al.
(författare)
-
Anterior tibial translation during different isokinetic quadriceps torque in anterior cruciate ligament deficient and nonimpaired individuals
- 2001
-
Ingår i: Journal of Orthopaedic and Sports Physical Therapy. - 0190-6011 .- 1938-1344. ; 31:1, s. 4-15
-
Tidskriftsartikel (refereegranskat)abstract
- Study Design: Factorial quasi-experimental design.Objectives: To quantify the effect of different levels of isokinetic concentric and eccentric knee extensor torques on the anterior tibial translation in subjects with anterior cruciate ligament (ACL) deficiency. Electromyogram (EMG) activity of 4 leg muscles was recorded in order to detect any co-activation of extensors and flexors.Background: The rehabilitation after an ACL injury is of importance for the functional outcome of the patient. In order to construct a rehabilitation program after that injury, it is important to understand the in vivo relationships between muscle force and tibial translation.Methods and Measures: Twelve patients with unilateral ACL injury and 11 uninjured volunteers performed 36 repetitions of a quadriceps contraction at different isokinetic concentric and eccentric torque levels, on a KinCom machine (60°•s-1), with simultaneous recordings of tibial translation (CA-4000) and EMG activity from quadriceps and hamstrings muscles. Tibial translations and EMG levels were normalized to the maximum of each subject.Results: The individual anterior tibial translation increased with increased quadriceps torque in a similar manner in both quadriceps contraction modes in all legs tested. During concentric mode, translation was similar in all groups, but during eccentric mode, the mean translation was 38% larger in the ACL injured knees. No quadriceps-hamstrings co-activation occurred in any test or group.Conclusions: An ACL deficient knee can limit the translation within a normal space during concentric muscle activity but not during eccentric activity. That limitation depends on other mechanisms than hamstrings co-activation.
|
|
| 8. |
- Kvist, Joanna, 1967-, et al.
(författare)
-
Anterior tibial translation during eccentric, isokinetic quadriceps work in healthy subjects
- 1999
-
Ingår i: Scandinavian Journal of Medicine and Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 9:4, s. 189-194
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of increasing isokinetic, eccentric quadriceps torques on sagittal translation of the tibia was examined in six healthy volunteers and compared to the translation at 20° of knee flexion during a drawer test with 90 N force. The tibial translation increased in a linear fashion with a mean of 0.5 mm per 20% torque increase. In 20° of knee flexion, 10% of eccentric quadriceps peak torque consumed 80% of the anterior tibial translation induced by the 90 N Lachman test while eccentric quadriceps peak torque utilized 100% of the translation at the same test. The in vivo relation between muscle force and tibial translation is of importance in the treatment of patients with injury to the cruciate ligaments. The results indicate that an already low eccentric quadriceps torque causes a tibial translation that reaches the limit of the passive knee joint displacement where strain is assumed to develop in the anterior cruciate ligament. Already low eccentric quadriceps torque levels may therefore be harmful during rehabilitation after anterior cruciate ligament surgery.
|
|
| 9. |
- Kvist, Joanna, 1967-, et al.
(författare)
-
Sagittal Plane Knee Translation and Electromyographic Activity During Closed and Open Kinetic Chain Exercises in Anterior Cruciate Ligament-Deficient Patients and Control Subjects
- 2001
-
Ingår i: American Journal of Sports Medicine. - 0363-5465 .- 1552-3365. ; 29:1, s. 72-82
-
Tidskriftsartikel (refereegranskat)abstract
- Using electrogoniometry and electromyography, we measured tibial translation and muscle activation in 12 patients with unilateral anterior cruciate ligament injury and in 12 control subjects. Measurements were made during an active extension exercise with 0-, 4-, and 8-kg weights and during squats on two legs and on one leg where the projection of the center of gravity was placed over, behind, and in front the feet. In the uninjured subjects, tibial translation increased with increasing load except during the squat with the center of gravity behind the feet, which produced the smallest translation. For the active extension exercises, translation was greater during eccentric activity. In the anterior cruciate ligament-injured knees, all squats resulted in similar translation, which was smaller than that during the active extension exercise. The highest muscle activation was seen during squats. Hamstring muscle activity was low. Increased static laxity in the anterior cruciate ligament-deficient knee can be controlled during closed but not during open kinetic chain exercises. Coactivation of the quadriceps and gastrocnemius muscles seems to be important for knee stability, whereas hamstring muscle coactivation was insignificant. To minimize sagittal translation during nonoperative management of anterior cruciate ligament-deficient knees, closed kinetic chain exercises are preferable to open kinetic chain exercises, and importance should be attached to the spontaneous coactivation of the quadriceps and gastrocnemius muscles.
|
|
| 10. |
|
|
