Table 1 shows the demographic data of the PF patients and normal controls, with no differences between the two groups.
Table 1. Demographic data in enrolled patients with plantar fasciitis and normal controls.
|
|
|
PF patients group
(n = 21)
|
Normal control group
(n = 21)
|
p-value
|
Gender (male/female)
|
10/11
|
13/8
|
|
Age (years) a
|
53 ± 4
|
51 ± 7
|
0.342
|
Height (cm) a
|
168 ± 3
|
166 ± 6
|
0.697
|
Weight (kg) a
|
66 ± 7
|
68 ± 4
|
0.778
|
Sports and activity, n (low:high)
|
18:3
|
16:5
|
0.401
|
Abbreviations: PF: plantar fasciitis.
aThe values are expressed as mean ± standard deviation.
Isokinetic strength
The strength of the quadriceps, but not the hamstring or GCM (p > 0.05, Table 2), was significantly decreased in the affected ankles of the patients with PF compared with those of the normal controls (115 ± 34.7 vs. 144 ± 26.1, respectively; p = 0.005, Table 2).
Table 2. Comparison of muscle strength and acceleration time in both ankles between the patients with plantar fasciitis and normal controls.
|
Affected ankles
|
Unaffected ankles
|
|
PF patients group
|
Normal control group
|
p-value
|
PF patients group
|
Normal control group
|
p-value
|
GCM strength
|
30 ± 11.4
|
41 ± 14.4
|
0.278
|
37 ± 10.9
|
41 ± 11.5
|
0.633
|
Quadriceps strength
|
115 ± 34.7
|
144 ± 26.1
|
0.005 a
|
126 ± 34.8
|
141 ± 21.9
|
0.110
|
Hamstring strength
|
61 ± 20.4
|
68 ± 12.7
|
0.182
|
74 ± 16.9
|
77 ± 8.2
|
0.370
|
GCM AT
|
30 ± 11.4
|
41 ± 14.4
|
0.009 a
|
37 ± 10.9
|
41 ± 11.5
|
0.278
|
Quadriceps AT
|
64 ± 25.2
|
48 ± 14.4
|
0.012 a
|
54 ± 25.2
|
51 ± 14
|
0.652
|
Hamstring AT
|
77 ± 21.9
|
56 ± 15.6
|
0.001 a
|
60 ± 13.7
|
58 ± 17.7
|
0.629
|
Forefoot pressure
|
70 ± 27.7
|
46 ± 15.7
|
0.001 a
|
52 ± 18.7
|
46 ± 15.7
|
0.277
|
Hindfoot pressure
|
65 ± 22.8
|
36 ± 15.2
|
0.000 a
|
44 ± 18.6
|
36 ± 15.2
|
0.115
|
Foot posture (VV index)
|
0.2 ± 0.3
|
0 ± 0.2
|
0.039 a
|
-0.1 ± 0.3
|
0 ± 0.2
|
0.861
|
Abbreviations: PF: plantar fasciitis, GCM: gastrocnemius, AT: acceleration time, VV index: valgus/varus index.
Note: The values are expressed as mean ± standard deviation
Measurement units for muscle strength and muscle reaction time were Nm kg−1 × 100 and milliseconds, respectively.
aStatistically significant
Muscle reaction time (AT)
The AT of the hamstring and quadriceps muscles was significantly greater in the affected ankles of the PF group than in those of the control group (hamstring: 77 ± 21.9 vs. 56 ± 15.6, p = 0.001, quadriceps: 64 ± 25.2 vs. 48 ± 14.4, p = 0.012, Table 2), whereas the AT of the GCM muscle was significantly lower in the PF patients than in the normal controls (30 ± 11.4 vs. 41 ± 14.4, p = 0.009, Table 2).
Correlations between the strength and reaction time of the quadriceps, hamstring, and GCM muscles
The strength of the GCM muscle in the affected ankles showed a significant positive correlation with the strength of the hamstring muscle (r = .634, p = .002, Table 3) but not of the quadriceps muscles (p > 0.05, Table 3). The AT of the GCM muscle in the affected ankles showed a significant negative correlation with the strength (r = -.598, p = .004, Table 3) and AT (r = -.472, p = .031, Table 3) of the quadriceps muscle but not the hamstring muscle (p > 0.05, Table 3).
Table 3. Correlations between the muscle strength and muscle reaction time.
Parameters
|
Affected ankles
|
Unaffected ankles
|
GCM strength
|
GCM AT
|
GCM strength
|
GCM AT
|
Quadriceps strength
|
PCC (r)
|
.289
|
-.598
|
.277
|
-252
|
|
p-value
|
.204
|
.004 a
|
.225
|
.271
|
Hamstring strength
|
PCC (r)
|
.634
|
-.371
|
.632
|
-.113
|
p-value
|
.002 a
|
.098
|
.002 a
|
.627
|
Quadriceps AT
|
PCC (r)
|
-.533
|
-.472
|
-.189
|
.080
|
p-value
|
.013 a
|
.031 a
|
.412
|
.732
|
Hamstring AT
|
PCC (r)
|
-.357
|
.212
|
.213
|
-.351
|
p-value
|
.112
|
.356
|
.354
|
.119
|
Abbreviations: PCC: Pearson’s correlation coefficient, GCM: gastrocnemius, AT: acceleration time.
aStatistically significant
Foot pressure and posture (VV index)
Forefoot and hindfoot pressure were significantly greater in the affected ankles of the patients with PF than in those of the normal controls (forefoot: 70 ± 27.7 vs. 46 ± 15.7, p = 0.001, heel: 65 ± 22.8 vs. 36 ± 15.2, respectively; p = 0.000, Table 2). The VV index values indicated hindfoot valgus in the affected ankles of the patients with PF compared with those of the normal controls (+0.2 ± 0.3 vs. 0 ± 0.2, respectively; p = 0.039, Table 2).
In the unaffected ankles, there were no significant differences in the strength and reaction time of the quadriceps, hamstring, and GCM muscles or the foot pressure and posture between the PF group and the control group (p > 0.05, Table 2).