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Table 1 Basic science PAFOs tested on healthy subjects in walking experiments

From: Powered ankle-foot orthoses: the effects of the assistance on healthy and impaired users while walking

Ref. Actuation (Pf/Df) Control Weight PAFO Subjects Conditions (n. sessions / repetitions) Ul / Bl Portable Aim Outcomes
Ferris, 2005 [29] 1PAM (Pf) + 1PAM (Df) PMc (SOL / TIB) 1.6 kg 1 H training: 60 min; test: 6N-6U-30P(Pf)-30P(Df) (1sess) / no Design lightweight orthosis for powered Pf and Df Pf assist: SOL reduced 47%, TIB increased 10% w.r.t. U; Df assist: SOL increased 10%, TIB reduced 20% w.r.t. U
Ferris, 2006 [30] 1PAM (Pf) + 1PAM (Df) PMc (SOL / TIB) 1.7 kg 1 H P (1 sess) / no Improve design of PAFO in Ferris, 2005 [29] Design improved: easier to don-doff, more comfortable
Galle, 2013 [43] PAM (Pf) P-Bc 0.76 kg 9 H 24P-4U Bl no Assess the effects of adaptation on the users Metabolic cost of walking and lower limbs muscle activation decrease from beginning to adapted period
Gordon, 2006 [44] 1 / 2 PAM (Pf) P-Bc 1.3 / 1.7 kg 3 H training: 1 min, test: 20secN-20secU-20secP (2 muscle configurations and 4 speeds) (2sess) Ul no Examine effect of walking speed and amount of assistance Ankle more plantarflexed in double PAM configuration, but similar total moments
     1 H training: 1 min; test: 20secU-20secP (3 muscle lengths)   no Examine the effect of PAM length Middle length of PAM is optimal
Gordon, 2007 [31] PAM (Pf) PMc (SOL) 1.2 kg 10 H 10U-30P-15U (2 sess) Ul no Examine adaptation of users and whether adapted pattern is retained in time Users learn to use less their muscles when assistance is provided and can retain this information
Kao, 2009 [32] PAM (Df) PMc (TIB) continuous / 5 H 10U-30P-15U (2 sess) Ul no Examine how subjects adapt to Df assistance TIB reduced only in initial stance in group continuous; in both groups TIB activity in swing is similar to U
   PMc (TIB) only in swing   5 H      
Kao, 2010 [33] 2 PAM (Pf) PMc (SOL) 1.08 kg 11 H 10U-30P-15U (2 sess) Ul no Determine if adaptation depends on the amount of assistance provided Higher amount of assistance leads to longer adaptation time
Kinnaird, 2009 [34] PAM (Pf) PMc (MG) 1.23 kg 10 H 10U-30P-15U (2 sess) Ul no Assess how nervous system adapts to external assistance Main reduction in SOL (muscle replaced by actuation), however also MG reduced to modulate action PAFO
  1. The type of actuator, the weight and portability of the device, the protocol, the main goal and outcomes of each study are reported
  2. H: healthy users; PAM: pneumatic artificial muscle; P-Bc, PMc: phase-based and proportional myoelectric controller; Pf, Df: plantarflexion and dorsiflexion; SOL, TIB, MG: soleus, tibialis anterior and medial gastrocnemius muscles; N, U, P: normal walking, unpowered and powered walking condition; Ul, Bl: uni-/bi-lateral PAFO; the protocol code defines the conditions and the timings in minutes (unless contrary indication) used for each session, e.g. xPyUzN means x minutes of powered walking, y minutes of unpowered walking and z minutes of normal walking. In the works in which different experiments were performed (for example, different control strategies) the common information between the experiments (for example, same condition) is reported only once