Upper Limb Associated Reactions: The Relationship Between Movement Kinematics and Muscle Activity in Seated Versus Walking Testing

Lower limb muscle performance during a closed chain single leg squat and a squat jump in people with leg weakness after stroke: A comparative study

Objective:

To determine if the intention to perform an exercise at speed leads to beneficial alterations in kinematic and kinetic components of the movement in people with post-stroke hemiplegia.

Design:

Comparative study.

Setting:

Subacute metropolitan rehabilitation hospital.

Participants:

Convenience sample of patients admitted as an inpatient or outpatient with a diagnosis of stroke with lower limb weakness, functional ambulation category score ≥3, and ability to walk ≥14metres.

Methods:

Participants performed a single leg squat exercise on their paretic and nonparetic legs on a leg sled under three conditions: 1) self-selected speed (SS), 2) fast speed (FS), 3) jump squat (JS). Measures of displacement, flight time, peak concentric velocity, and muscle excitation (via electromyography) were compared between legs and conditions.

Results:

Eleven participants (age: 56 ± 17 years; median time since stroke onset: 3.3 [IQR 3,41] months) were tested. All participants achieved a jump during the JS, as measured by displacement and flight time respectively, on both their paretic (0.25 ± 0.16 m and 0.42 ± 0.18 s) and nonparetic (0.49 ± 0.36 m and 0.73 ± 0.28 s) legs; however it was significantly lower on the non-paretic leg (p < 0.05). Peak concentric velocity increased concordantly with intended movement speed (JS-FS paretic: 0.96 m/s, non-paretic: 0.54 m/s; FS-SS paretic 0.69 m/s, nonparetic 0.38 m/s; JS-SS paretic 1.66 m/s, non-paretic 0.92 m/s). Similarly, muscle excitation increased significantly (p < 0.05) with faster speed for the paretic and nonparetic vastus lateralis. For gastrocnemius, the only significant difference was an increase during nonparetic JS vs. SS and FS.

Conclusions:

Speed affects the kinematic and kinetic components of the movement. Performing exercises ballistically may improve training outcomes for people post-stroke.

Lower limb muscle performance during a closed chain single leg squat and a squat jump in people with leg weakness after stroke: A comparative study

OBJECTIVE

To determine if the intention to perform an exercise at speed leads to beneficial alterations in kinematic and kinetic components of the movement in people with post-stroke hemiplegia.

DESIGN

Comparative study.

SETTING

Subacute metropolitan rehabilitation hospital.

PARTICIPANTS

Convenience sample of patients admitted as an inpatient or outpatient with a diagnosis of stroke with lower limb weakness, functional ambulation category score ≥3, and ability to walk ≥14metres.

METHODS

Participants performed a single leg squat exercise on their paretic and nonparetic legs on a leg sled under three conditions: 1) self-selected speed (SS), 2) fast speed (FS), 3) jump squat (JS). Measures of displacement, flight time, peak concentric velocity, and muscle excitation (via electromyography) were compared between legs and conditions.

RESULTS

Eleven participants (age: 56 ± 17 years; median time since stroke onset: 3.3 [IQR 3,41] months) were tested. All participants achieved a jump during the JS, as measured by displacement and flight time respectively, on both their paretic (0.25 ± 0.16 m and 0.42 ± 0.18 s) and nonparetic (0.49 ± 0.36 m and 0.73 ± 0.28 s) legs; however it was significantly lower on the non-paretic leg (p p Conclusions: Speed affects the kinematic and kinetic components of the movement. Performing exercises ballistically may improve training outcomes for people post-stroke.

Potential contributing factors to upper limb associated reactions in people with acquired brain injury: an exploratory study

PURPOSE

To determine which potential contributing factors are associated with upper limb associated reaction (AR) expression in individuals with acquired brain injury (ABI).

METHODS

Forty-two participants underwent three-dimensional motion analysis at self-selected walking speed to generate the AR outcome measure, quantifying their upper limb kinematic deviation compared to healthy controls. Clinical assessment included: upper and lower limb hypertonicity, spasticity and strength, balance, dynamic walking stability, arm and leg function, anxiety, arm pain/discomfort, and fear of falling.

RESULTS

Significant, moderate-to-strong correlations (r = 0.42-0.74, p < 0.05) existed between upper limb ARs and both hypertonicity and spasticity of the upper limb muscles and the knee extensors. Significant, moderate correlations to ARs (r = 0.42-0.59, p < 0.05) existed for balance, dynamic stability, upper limb strength, and arm function. The severity of AR was significantly different between those with and without hypertonicity of the four tested upper limb muscles, elbow and long finger flexor spasticity, knee extensor spasticity, and reduced dynamic stability (p < 0.05; effect sizes ≥0.80). However, these contributing factors were not present in all participants.

CONCLUSIONS

Associated reactions are complex and multi-factorial. There were several significant correlations indicating that factors may influence AR severity. While positive upper motor neuron syndrome features should be prioritised for clinical assessment, these factors are not prerequisites for ARs.IMPLICATIONS FOR REHABILITATIONUpper limb associated reactions are a complex and multi-factorial phenomenon.Upper limb muscle hypertonicity and spasticity should be prioritised for assessment; however, they are not prerequisites for associated reactions.Hypertonicity and spasticity should be differentiated as they may have differing relationships to associated reactions.Knee extensor hypertonicity and spasticity, postural stability, upper limb strength, and arm function may also be contributing factors to consider.