Calf-raise senior: a new test for assessment of plantar flexor muscle strength in older adults: protocol, validity, and reliability

Figures & data

Figure 1 Flow diagram of attendance to the assessment sessions.

Abbreviations: CRS, calf-raise senior; FF, functional fitness.

Figure 2 Protocol description of the calf-raise senior test.

Figure 3 Plantar flexor strength test protocol in the BiodexSystem III machine.

Table 1 Sample characterization: demographic, anthropometric, health, functional fitness, and strength parameters

Parameters	n	$\overline{X}\pm \text{SD}(\text{mean})$
Demographic parameters
Age (years)	41	73.90±7.71 (71.50)
Weight (kg)	41	65.70±10.78 (65.00)
Height (m)	41	161.40±0.10 (1.60)
BMI (kg/m^2)	41	25.15±2.72 (25.00)
Health parameters
General health perception (1–4)	41	3.70±0.90 (4.00)
Medicine intake (total number of medicines a day)	41	1.76±1.04 (1.00)
Falls (number of falls in previous year)	41	0.50±0.90 (0.00)
FF parameters
CS test	41	17.44±7.10 (19.00)
U&G	41	5.95±0.50 (4.70)
2 minutes	41	83.10±39.53 (97.00)
FAB4	41	3.85±0.42 (4.00)
FAB5	41	3.17±1.28 (4.00)
FAB6	41	2.98±0.19 (4.00)
FAB7	41	3.39±1.02 (4.00)
TFFS	41	12.00±0.74 (14.00)
CRS trial 1	41	33.03±13.48 (32.50)
CRS trial 2	41	36.46±14.36 (38.00)
Physical activity (minutes a day)	28	31.83±28.32 (24.60)
Strength parameters
RFD	34	176.57±92.85 (163.45)
MISM torque	34	68.86±25.96 (67.15)
MISK torque	34	65.16±23.72 (63.30)

Notes: U&G, 8 foot up and go; 2 minutes, 2-minute step; FAB4, step up and over a bench; FAB5, tandem walk along a line; FAB6, stand on one leg; FAB7, stand on a foam with eyes closed.

Abbreviations: BMI, body mass index; CRS, calf-raise senior; CS, chair stand; FF, functional fitness; MISK, maximal isokinetic; MISM, maximal isometric; RFD, rate of force development; SD, standard deviation; TFFS, total functional fitness score.

Table 2 Results of intra- and interrater agreement analysis of CRS test

Trials and intrarater statistical factors	Rater 1 $\overline{X}\pm \text{SD}$	Rater 2 $\overline{X}\pm \text{SD}$	Rater 1 + rater 2 $\overline{X}\pm \text{SD}$	r	ICC (95% CI)
Trial 1	31.62±7.22	31.00±6.70	31.31±6.97	0.88	0.93 (0.78–0.98)
Trial 2	33.00±7.23	31.54±6.70	32.27±7.01	0.92	0.84 (0.72–0.97)
Total	32.31±7.26	31.27±6.71	31.79±7.01
Difference	1.38±4.09	0.54±4.50	0.96±4.32
r	0.78	0.84
ICC (95% CI)	0.79 (0.60–0.96)	0.84 (0.72–0.97)

Note: Mean ± SD, Pearson’s coefficient of correlation (r), and the ICC_2,1 with 95% CIs of raters and trials are presented.

Abbreviations: CI, confidence interval; CRS, calf-raise senior; ICC, intraclass correlation coefficient; SD, standard deviation.

Table 3 Comparison among groups of age, PA, FF, and sex and CRS scores

Variables	Groups	n	$\overline{X}\pm \text{SD}$	P-value	Effect size	CRS r
Age	<72 years	20	43.95±12.55	0.001**	1.67a	−0.642**
	≥72 years	20	28.90±2.54
PA	Physically active	14	41.64±11.69	0.001**	1.44a	0.639**
	Sedentary	12	26.50±9.14
FF	High functional	18	46.23±27.2	0.000**	1.75a	0.825**
	Low functional	21	10.62±8.95
Sex	Female	23	31.65±13.41	0.014*	0.81a	0.408**
	Male	18	42.61±13.46

Notes: Mean ± SD of CRS scores in groups of age (<72 years vs ≥72 years); PA, FF, and sex (female vs male); P-values from comparison between groups (Student’s t and Mann–Whitney tests); and Pearson’s or Spearman’s correlation coefficient between CRS scores and group variables are presented.

a |d|.0.5 – medium effect size, here considered as clinical relevant differences between group means.

* P<0.05.

** P<0.001.

Abbreviations: CRS, calf-raise senior; FF, functional fitness; PA, physical activity; SD, standard deviation.

Table 4 Correlations between strength measures and CRS scores

Variables	CRS score
	r	R^2	F	B	SE B	Beta
MISM torque	0.87**	0.75	97.53**	0.46	0.05	0.87
MISK torque	0.86**	0.74	86.27**	0.49	0.05	0.86
RFD	0.77**	0.59	46.08**	0.11	0.02	0.77

Notes: Pearson’s correlation coefficient (r) and simple linear regression (Enter method) analysis between CRS and strength parameters.

** P<0.001.

Abbreviations: CRS, calf-raise senior; MISK, maximal isokinetic; MISM, maximal isometric; RFD, rate of force development; SE, standard error.

Figure 4 Linear regression analysis among strength measures (MISM torque, MISK torque, and RFD) and CRS test scores.

Abbreviations: CRS, calf-raise senior; MISK, maximal isokinetic; MISM, maximal isometric; reps, repetitions; RFD, rate of force development.

Figure 5 ROC curves between CRS scores of subjects presenting best and worst results in isometric tests.

Abbreviations: ROC, receiver-operating characteristics; CRS, calf-raise senior.