Table 2 Aims, protocol and key findings of non-intervention studies.
Study | Aims | Participant characteristics | Medication | Walking surface | Walking task | Key findings |
|---|---|---|---|---|---|---|
Albani et al.66 | Evaluated the relationship between freezing of gait (FoG) in PD and no FoG and EMG patterns during treadmill walking. | PD (n = 10) Age: 64 ± 13 Gender: not reported H&Y: 3–4 (FoG) 1.5–2.5 (no FoG) UPDRS-III: 53.2 ± 14.7 (FoG) 24.8 ± 6.5 (no FoG) HOA (n = 7) Age: 63 Gender: 4m/3f | ON | Treadmill | Walking for 60 s at belt speed of 0.3 m/s and 1.5 m/s. | Decreased left MG amplitude during stance in the PD groups compared to HOA. Greater left TA activity during swing in the PD groups compared to HOA at slow walking speed. |
Arias et al.67 | Investigated the effect of walking speed on muscle coactivation and differences between healthy adults and PD groups. | PD (n = 20) Age: 68.3 ± 6.9 Gender: not reported H&Y: 3–4 HOA (n = 20) Age: 66.6 ± 7.8 Gender: not reported HYA (n = 7) Age: 21.9 ± 1.5 Gender: not reported | ON or OFF | Overground 6 m walkway | Four trials of walking at self-selected speed followed by fast walking (FW). Walking to a metronome set at 50–110% of FW cadence. | No association between coactivation index and gait speed was reported. High variability of coactivation between individuals. No difference between usual walking and walking to a metronome. |
Bello et al.73 | Compared differences in EMG between PD and HOA. Differences in EMG between overground, treadmill and a treadmill simulator walking in PD. | PD (n = 9) Age: 71.0 ± 6.0 Gender: 8m/1f H&Y: = 3 UPDRS-III: 38.7 ± 7.3 HOA (n = 9) Age: 71.0 ± 8.6 Gender: 8m/1f | ON | Overground 1.3 m walkway Treadmill walking Treadmill simulator walking | Three trials of walking at self-selected walking speed. Three minutes walking overground on the treadmill at self-selected speed. Three minutes walking on a treadmill simulator. | Decreased activity of TA for load phase (PD and HOA). Lower coactivation of BF/VL for swing phase (PD and HOA) and single support (PD only). Lower coactivation of TA/GM for single support (PD and HOA). |
Dietz et al.63 | Evaluated EMG of the lower limb during various speeds of treadmill. Investigated interlimb coordination by varying split-belt treadmill conditions. | PD (n = 14) Age: 61 ± 11.4 Gender: not reported Movement disorder: 1–2 (scale not stated) HOA (n = 10) Age: 60.6 ± 6 Gender: not reported | ON | Split-belt treadmill | Walked on treadmill at speeds of 0.25, 0.5, 0.75 and 1.0 m/s. Various combinations for both legs for 60 s per condition. | Greater coactivation in PD compared to HOA, independent of treadmill walking condition. Less modulation of muscle activity, particularly for MG. Longer double support in PD. Decreased ability of PD to change stride frequency with treadmill speed. |
Investigated the effect of body unloading on lower limb EMG during treadmill walking. | PD (n = 11) Age: 63.4 ± 12.7 Gender: not reported H&Y: 1.5–3 UPDRS: 27.3 ± 9.4 HOA (n = 7) Age: 63.0 ± 6.5 Gender: not reported HYA (n = 9) Age: 26.8 ± 3.3 Gender: not reported | ON | Treadmill | Walked on treadmill at a speed of 0.34 ± 0.14 m/s for each body unloading condition. | MG and RF activity decreased during unloading. MG was less sensitive to unloading in PD. TA and BF activity showed minimal change during unloading. | |
Jenkins et al.62 | Examined effects of increasing plantar cutaneous sensation with a ribbed insole on EMG and gait parameters. | PD (n = 40) Age: 65.4 ± 8.0 Gender: 24m/16f H&Y: 1–3 UPDRS-III: 22.6 ± 8.4 HOA (n = 40) Age: 64.7 ± 7.7 Gender: 15m/25f | ON | Overground 6.1 m walkway | Ten walking trials at self-selected walking speed under two conditions: 5 with ribbed insole 5 with conventional flat insole. | In PD, TA peak activity (loading phase) occurred later than in HOA. The effect of a ribbed insole resulted in earlier peak activation of TA (loading phase). |
Miller et al.69 | Investigated effect on EMG symmetry and variability following a 3-week RAS gait training programme. Comparisons made between individuals with PD and HOA. | PD (n = 18) Age: 71 ± 8 Gender: not reported H&Y: 2–3 HOA (n = 19) Age: 68 ± 7 Gender: not reported | ON | Overground 8 m walkway | Two trials of walking at self-selected walking speed. Recordings taken before and after 3-week RAS intervention. | No RAS: PD showed greater shape variability of TA and MG vs HOA. TA displayed the greatest shape variability in both groups. Phase variability for MG was smaller in PD vs. HOA. Higher asymmetry of TA and MG was reported in PD. RAS: Walking speed increased MG and TA variability and TA asymmetry decreased in PD. In HOA, no significant changes were reported. |
Mitoma et al.65 | Compared EMG and kinematics in individuals with PD to HOA during walking. | PD (n = 16) Age: 65 ± 10.9 Gender: 11m/5f H&Y: 1–4 HOA (n = 17) Age: 74.4 ± 5.8 Gender: 9m/8f | ON | Overground 6 m walkway. | Ten trials at preferred walking speed. Three or more consecutive cycles recorded. | Lower distal muscle activity (particularly TA during single support) and greater proximal muscle activity (swing phase) in PD vs. HOA. Difference in distal muscles between PD and CA; lower activity of TA and gastrocnemius (early stance). In PD group, there was reduced ∆EMG/∆ankle angle for the plantarflexors compared to HOA. |
Rodriguez et al.70 | Investigated differences in motor modules between individuals with PD and HOA. Compared muscle weighting vectors and activation profiles of the motor modules between individuals with PD and HOA. Relationships between motor modules and gait mechanics in PD and HOA. | PD (n = 15) Age: 66.6 ± 7.8 Gender: not reported HOA (n = 14) Age: 66.2 ± 7.1 Gender: not reported | ON | Split-belt treadmill | Ten minutes at self-selected walking speed. | PD required fewer modules compared to healthy controls. Descriptively, PD exhibit an altered temporal activation profile of modules. The percent variance accounted for MG, SM and BF was significantly higher for PD. No significant difference in speed between PD and HOA. |
Rose et al.72 | Investigated the effect of 8-week high intensity locomotor training using a positive-pressure treadmill on knee extensor flexor and extensor activity. | PD (n = 13) Age: 62 ± 6.4 Gender: 13m H&Y: 2–3 HOA (n = 8) Age: 53 ± 4.4 Gender: 8m | ON | Anti-gravity treadmill | Five walking trials 70 s long at 3 km/h treadmill speed. Three recordings taken: Training day 2 Midway through training Post training Eight-week treadmill training (1 h × 3/week) involving running, walking, bodyweight support, different speeds and varied locomotion (chassé, skipping, jumping, sprints) | Knee extensors VL and VM were active for a longer proportion of the gait cycle and displayed higher peak activation in PD vs. HOA. BWS decreased activity duration of knee extensors but increased knee flexor duration. |
