Inclined treadmill walking kinetics of the non-paretic leg in early post-stroke survivors: an observational case-control study.

Early post-stroke survivors walked significantly slower than matched controls on the treadmill.

• Stroke survivors' preferred walking speed was 0.6 km/hr compared to 2.15 km/hr for controls.
• The study included fourteen early post-stroke survivors (three months post-event or less) and fourteen matched controls.
• Both groups shared similar demographic characteristics despite the speed difference.
• Preferred walking speed was used as a covariate in the mixed two-way repeated measures ANCOVA.

The non-paretic leg of stroke survivors showed lower vertical GRF peak amplitudes during weight acceptance (F1) and push-off (F3) phases compared to controls, regardless of incline condition.

• F1 (weight acceptance) mean values: controls 1.11 vs. patients 1.04 (normalized units).
• F3 (push-off) mean values: controls 1.09 vs. patients 1.03 (normalized units).
• These differences were observed regardless of treadmill grade (0% or 6%).
• Mixed two-way repeated measures ANCOVA was used with preferred walking speed as a covariate.

Stroke survivors showed higher mid-stance vertical GRF (F2) in the non-paretic leg compared to controls, suggesting a flatter GRF profile.

• F2 (mid-stance) mean values: controls 0.92 vs. patients 0.98 (normalized units).
• A higher F2 relative to lower F1 and F3 indicates a flatter vertical GRF profile.
• This pattern was interpreted as indicative of compensatory or pathological gait mechanisms.
• The flatter profile suggests altered weight distribution across the stance phase in the non-paretic limb.

Stroke survivors demonstrated lower impulse magnitudes across all four impulse intervals (J1–J4) in the non-paretic leg compared to controls.

• J1: controls 25.46 vs. patients 18.74.
• J2: controls 21.37 vs. patients 13.46.
• J3: controls 22.38 vs. patients 15.71.
• J4: controls 22.16 vs. patients 18.19.
• These differences were observed regardless of incline condition.

Inclined treadmill walking (6%) produced differential push-off responses between controls and stroke survivors, with controls increasing F3 and stroke survivors decreasing F3.

• Controls showed increased F3 from grade 0% (1.06) to grade 6% (1.12).
• Stroke survivors showed reduced F3 from grade 0% (1.05) to grade 6% (1.01).
• This divergent response was interpreted as impaired push-off mechanics in stroke survivors during inclined walking.
• Both groups showed increased F1 (Grade 0%: 1.06 vs. Grade 6%: 1.10) and decreased F2 (Grade 0%: 0.97 vs. Grade 6%: 0.93) with incline, regardless of group.

The study was designed as an observational case-control study examining vertical GRF profiles and their variabilities during level and inclined treadmill walking.

• Participants walked at 0% and 6% grade incline on a treadmill at their preferred speeds.
• Key vertical GRF variables included peak amplitudes (F1, F2, F3), impulses (J1–J4), timing to each peak, and loading/unloading rates, along with their respective variabilities.
• Only GRF components corresponding to the non-paretic leg of stroke survivors were investigated.
• The study focused on early post-stroke survivors defined as three months post-event or less.

The authors concluded that rehabilitation approaches should target both legs individually rather than treating the non-paretic leg as healthy.

• The non-paretic leg demonstrated measurable biomechanical differences from healthy controls.
• The authors recommend focusing on motor control and force steadiness rather than simply strength.
• This approach was suggested to more effectively reduce maladaptive variability and enhance safe and efficient walking patterns.
• The findings were considered particularly relevant to real-world mobility challenges represented by inclined walking.