Isokinetic Outcomes Research Articles

Isokinetic knee muscle strength comparison after enhanced recovery after surgery (ERAS) versus conventional setup in total knee arthroplasty (TKA): a single blinded prospective randomized study

PurposeTotal knee arthroplasty (TKA) combined with the concept of enhanced recovery is of continued worldwide interest, as it is reported to improve early functional outcome and treatment quality without increasing complications. The aim of the study was to investigate isokinetic knee muscle strength after cemented TKA in combination with an enhanced recovery after surgery (ERAS) compared to a conventional setup.MethodsIn the single blinded prospective randomized study, 52 patients underwent navigated primary cemented TKA within an ERAS (n = 30) or a conventional setup (n = 22). Preoperatively, five days and four weeks after surgery isokinetic knee muscle strength with BIODEX-type measuring device (peak torque in Nm, work in Joules and power in Watt) and subjective patient-related outcome measures (PROMs) were investigated.ResultsThe ERAS group showed significantly better outcomes in knee flexion at 180°/s (peak torque (Nm) p = 0.047, work (J) p = 0.040 and power (W) p = 0.016) 5 days postoperatively. The isokinetic measuring at knee extension 60°/s and 180°/s demonstrated no significant difference. The PROMs showed that patients were satisfied with the postoperative results in both groups. After 4 weeks, there was no longer a significant difference in isokinetic measuring at knee extension and flexion between the ERAS and conventional group.ConclusionsTKA with the concept of ERAS improves excellent isokinetic outcome and patient satisfaction. The isokinetic muscle strength measurement can help patients and surgeons to modify expectations and improve patient satisfaction.

Analyses of Isokinetic Thigh Muscle Strength: Camera-Based Assessment Alters the Magnitude, but Not the Message

ABSTRACT Background: Thigh muscle strength capacities are major modifiable risk factors for knee and thigh muscle injuries. Therefore, their valid assessment is essential. Most isokinetic knee tests are conducted in a seated position and rely on dynamometer-based data. However, their accuracy is doubtful because axis alignment is erroneous. Purpose: This study investigated if hip angle (flexed vs. extended) and assessment method (dynamometer-based vs. camera-based) affect isokinetic outcome parameters. Methods: Sixteen healthy male participants (27 years, 184 cm, 80 kg) performed discrete isokinetic tests of the knee flexors and extensors (60°/s) while their kinematics were captured (100 fps). Results: Both assessment methods revealed very strong linear relationships (94% ≤ R 2 ≤ 98%) although peak moments (d ≤ 0.87), contractional work (d ≤ 1.26), and functional knee flexor:extensor ratios (d ≤ 0.81) significantly differed. Seated knee flexor tests demonstrated the largest knee trajectory center’s misalignment (x = 4.0 cm, z = −2.5 cm; 1.37 ≤ d ≤ 4.74). Conclusion: Hip-angle induced kinematic changes did not affect the relation between the lever arms, thus causing highly proportional deviations of kinetic parameters. The assessment method altered the magnitude, but not the message of isokinetic knee tests, which should be preferentially performed with extended hip joint to improve axis alignment. Knowledge of these kinetic and kinematic interactions assists practitioners and scientists with isokinetic tests and/or rehabilitation training to ensure reasonable interpretations of gathered isokinetic outcomes.

Motor-based priming: isokinetic outcomes of aerobic exercise in children with spastic diplegia

IntroductionPriming is a behavioural change generated by preceding stimuli. Priming physical activities with aerobic exercise could improve performance and function. The study aimed to investigate the effect of aerobic exercise before a rehabilitation program on quadriceps peak torque in children with cerebral palsy of spastic diplegia.MethodsOverall, 32 patients participated in this study; they were randomly assigned to 2 groups. Patients in the control group (A) engaged in a selected physical therapy program, while those in the experimental group (B) performed aerobic exercise by using a bicycle ergometer followed by application of the same selected physical therapy program as received by group A. The treatment programs were conducted 3 times per week for 12 successive weeks. Measurements obtained included concentric peak torque of quadriceps muscle at 30° as well as 90°. These measures were recorded 2 times: before and after the application of the treatment program.ResultsThere were statistically significant differences when comparing pre- and post-treatment mean values in each group. Also, there was a significant difference in favour of group B with regard to post-treatment mean values.ConclusionsIn accordance with the applied procedures, aerobic exercise is effective in improving quadriceps peak torque in children with cerebral palsy of spastic diplegia when applied before a physical therapy rehabilitation program.

Swing Phase Mechanics of Maximal Velocity Sprints-Does Isokinetic Lower-Limb Muscle Strength Matter?

Concentric hip and eccentric knee joint mechanics affect sprint performance. Although the biarticular hamstrings combine these capacities, empirical links between swing phase mechanics and corresponding isokinetic outcome parameters are deficient. This explorative study aimed (1)to explain the variance of sprint velocity, (2)to compare maximal sprints with isokinetic tests, (3)to associate swing phase mechanics with isokinetic parameters, and (4)to quantify the relation between knee and hip joint swing phase mechanics. A total of 22 sprinters (age = 22y, height = 1.81m, weight = 77kg) performed sprints and eccentric knee flexor and concentric knee extensor tests. All exercises were captured by 10 (sprints) and 4 (isokinetics) cameras. Lower-limb muscle balance was assessed by the dynamic control ratio at the equilibrium point. The sprint velocity (9.79 [0.49]m/s) was best predicted by the maximal knee extension velocity, hip mean power (both swing phase parameters), and isokinetic peak moment of concentric quadriceps exercise (R2 = 60%). The moment of the dynamic control ratio at the equilibrium point (R2 = 39%) was the isokinetic parameter with the highest predictive power itself. Knee and hip joint mechanics affected each other during sprinting. They were significantly associated with isokinetic parameters of eccentric hamstring tests, as well as moments and angles of the dynamic control ratio at the equilibrium point, but restrictedly with concentric quadriceps exercise. The maximal sprints imposed considerably higher loads than isokinetic tests (eg,13-fold eccentric knee joint peak power). Fast sprinters demonstrated distinctive knee and hip mechanics in the late swing phase, as well as strong eccentric hamstrings, with a clear association to the musculoarticular requirements of the swing phase in sprinting. The transferability of isokinetic knee strength data to sprinting is limited inter alia due to different hip joint configurations. However, isokinetic tests quantify specific sprint-related muscular prerequisites and constitute a useful diagnostic tool due to their predicting value to sprint performance.

Structural and biomechanical changes in shoulders of junior javelin throwers: a comprehensive evaluation as a proof of concept for a preventive exercise protocol.

The purpose of this study was to develop a preventive exercise protocol based on structural and functional changes present in shoulder joints of young throwing athletes. As a proof of concept, these changes were previously evaluated in a cross-section of high-performance junior javelin throwers. Thirteen members of the German and Bavarian junior javelin squad (mean age 17.5±0.8years) completed a systematic clinical examination, shoulder range of motion (ROM) measurement, and were scored with standardized clinical tools. 3.0 tesla magnetic resonance imaging (MRI) was conducted on both shoulders. Bilateral three-dimensional analysis of the scapulothoracic motion during multiplanar humeral elevation and isokinetic strength testing of the shoulder internal and external rotators was accomplished. Based on the findings, a preventive exercise protocol was confirmed. Dominant internal ROM was significantly decreased (dominant 48°±20° vs. non-dominant 57°±19°; P=0.006) and dominant external ROM increased (dominant 117°±15° vs. non-dominant 107°±10°; P=0.008). MRI revealed posterosuperior intraosseous cysts of the humeral head with a size larger than >3mm in 69% of the dominant shoulders and only in 15% in the non-dominant shoulders. Motion analysis of the static scapular resting position was significantly different between dominant and non-dominant sides regarding anterior tilt (dominant>non-dominant, mean difference 4.2°, P=0.010) and retraction (dominant>non-dominant, mean difference 2.4°, P=0.038). Dominant scapular anterior tilt during flexion and abduction was significantly increased (-4.3°, P=0.006; -3.4°, P=0.046). Dominant retraction was significantly increased during abduction (-2.3°, P=0.040). Isokinetic outcome parameters presented nonsignificant bilateral differences. Elite junior javelin throwers already present structural (humeral intraosseous cysts) and biomechanical changes (ROM deficits and asymmetric scapulothoracic motion patterns), even if they have no history of major shoulder pain or injury. A novel exercise protocol was developed in order to address the complex of alterations in a comprehensive way. Preventive diagnostics in combination with a systematic all-year preventive exercise intervention might be one option to detect and control risk factors of a symptomatic throwing shoulder at an early stage. IV.

Differential effect of Taekwondo training on knee muscle strength and reactive and static balance control in children with developmental coordination disorder: A randomized controlled trial

This randomized controlled trial aimed to investigate the effect of short-term intensive TKD training on the isokinetic knee muscle strength and reactive and static balance control of children with developmental coordination disorder (DCD). Among the 44 children with DCD (mean age: 7.6 ± 1.3 years) recruited, 21 were randomly assigned to undergo daily TKD training for 1h over three consecutive months, with the remaining 23 children being assigned to the DCD control group. Eighteen typically developing children (mean age: 7.2 ± 1.0 years) received no training as normal controls. Knee extensor and flexor muscle strength and reactive and static balance control were assessed using an isokinetic machine (with low, moderate and high movement velocities), a motor control test (MCT) and a unilateral stance test (UST), respectively. A repeated measures MANCOVA revealed a significant group through time interaction effect in isokinetic outcomes at 180°/s and in the UST outcome. Post hoc analysis demonstrated that DCD-TKD children's isokinetic knee muscle strength, specifically at 180°/s, was as high as that of the normal control children (p>0.0083) after TKD training. Moreover, UST body sway velocity was slower in the DCD-TKD group than in the DCD control group (p<0.001), and was comparable to that of the normal control group (p>0.05) after TKD training. However, no such improvement in balance was observed in the MCT (p>0.025). The results show that children with DCD who undergo a 3-month program of intensive TKD training experience improvements in isokinetic knee muscle strength at 180°/s and static single-leg standing balance control, but do not benefit from improved reactive balance control.

Effect of Subject Restraint and Resistance Pad Placement on Isokinetic Knee Flexor and Extensor Strength

Background:In clinical practice, several subject restraint and resistance pad placement variations are used when an isokinetic knee flexion/extension test is performed. However, it is unknown if these variations affect the outcome measures. The aims of this study were to determine if these setup variations affect isokinetic outcomes and to establish the smallest detectable difference for these setup variations.Hypothesis:Variation in isokinetic setup affects outcome measures.Study Design:Cross-sectional repeated-measures crossover study.Methods:Ten recreationally active adult men were examined with isokinetic dynamometry on 4 separate days. In the first 3 days, fully strapped and trunk-unstrapped testing was conducted with the resistance pad placed distally on the shin. On days 1 and 3, the unstrapped condition was performed first, followed by the strapped condition. On day 4, the resistance pad was placed proximal on the shin (anterior cruciate ligament testing).Results:There were no within-condition differences for days 1, 2, or 3 for the strapped and unstrapped conditions (P > 0.05). Between-condition comparisons were significant (eg, quadriceps peak torque, P < 0.001; hamstring peak torque, P = 0.043) for the strapped, unstrapped, and proximal resistance pad placement conditions. The strapped condition generally showed the largest torques, and the unstrapped, the least. The smallest detectable differences were relatively large (eg, quadriceps peak torque strapped = 20.6%). The greatest intraclass correlation values were found when strapped.Conclusions:Subject setup significantly influences isokinetic outcome measures at the knee. Since the strapped condition demonstrated the greatest repeatability, it is recommended. The smallest detectable differences were relatively high for all variables and should be considered in the interpretation of the effect size of interventions.Clinical Relevance:Subject setup strapping must be considered when investigating test-retest values or when comparing subjects after isokinetic testing at the knee. The fully strapped condition has the best repeatability and highest torque values.