Effects of warm-up exercises on self-assessed vocal effort

Figures & data

Figure 1. Flow chart of trial process with placement for vocal effort ratings (VER 1-4), vocal warm-up interventions (loud reading or SOVTE) and silence periods. The procedure was prefaced with a practice session and baseline recordings of vocal effort levels.

Flow chart showing trial process.

Figure 2. (Left) self-evaluation of vocal effort as designed by van Leer and van Mersbergen, first published in Journal of Voice, 2017 [16]. (Right) self-evaluation of vocal effort as presented in the experimental set-up.

Left: Borg CR-10 scale as originally published by van Leer and van Mersbergen, 2017. Right: Borg CR-10 scale presented at a slant, in the current study.

Figure 3. (Left) visual representation as shown prompt for ascending pitch glides (descending not shown). (Right) visual representation as shown prompt for ascending hills/accents for recorded pitch range during SOVTE (own material).

Two computer screens showing visual prompts for participants.

Figure 4. Absolute (left) and relative (right) changes in self-evaluated vocal effort. Bars represent standard error.

Left: results from absolute vocal effort ratings. Right: results from standardized vocal effort ratings.

Table 1. Individual vocal effort ratings (VER) at each given time point: VER 1–4 and within-subject standard deviation (WSSD).

			VER1		VER2	VER3	VER4
Group	Participant	Baseline rating	Pre silence I	Post silence I	Pre intervention	Post intervention	Post silence II	WSSD (VER 1–4)
Reading	F01_R1	1	1	1	1	2	0.5	0
	F05_R3	0	1	0	0.5	1	0.5	0.58
	F10_R1	1	2	2	3	3	3	0.58
	F12_R2	1	1	1	1	1	1	0
	F13_R3	1	2	1	2	2	1	0.58
	F17_R1	0.5	0.5	0.5	0.5	2	2	0
	F27_R2	0.5	1	0.5	1	2	0.5	0.29
	M03_R2	2	4	4	5	7	4	1.15
	M15_R4	0	0	0	0	0	0	0
	M19_R1	1	1	1	1	1	1	0
	M20_R3	0.7	1	1	1	1,7	0.7	0.17
	M21_R4	2	2	2	2	3	3	0
	M22_R2	2	2	2	2	2	2	0
SOVTE	F02_S1	0	0	0	0.5	0,5	0.5	0
	F04_S2	0	0.5	0	0.5	2	0	0.29
	F08_S1	1	3	0	2	7	0	1.53
	F14_S3	0.5	2	1	1	3	3	0.76
	F18_S1	2	3	2	3	2	2	0.58
	F24_S3	3	2	2	3	2	2	0.58
	F25_S4	0	0.5	0	0.5	1	0	0.29
	F26_S2	0	0	0	0	0,5	0	0
	M06_s3	2	2	2	2	5	3	0
	M07_S4	1	2	1	2	3	2	0.58
	M11_S2	0.5	1.2	0.5	1	1	0.5	0.4
	M16_S4	2	2	2	3	4	3	0
	M23_S1	2	2	2	2	2	2	0

Table 2. Aggregated group results, explaining mean and standard deviation (SD) of vocal effort ratings (VER) at four time points: VER 1–4 with time points compared within groups in total with Friedman’s test for repeated measures as well as at each time change with Wilcoxon’s signed rank test.

Repeated measures	Reading	SOVTE	Mann–Whitney U post hoc test reading vs. SOVTE
VER 1 mean (SD)	1.42 (.9968)	1.55 (1.0228)	U = 73.000, p = .541 NS
VER 2 mean (SD)	1.54 (1.3144)	1.58 (1.0576)	U = 79.000, p = .772 NS
Wilcoxon’s signed rank post hoc test VER 1 vs. VER 2	Z = −1.089, p = .276 NS	Z = −.108, p = .914 NS
VER 3 mean (SD)	2.12 (1.6800)	2.54 (1.8870)	U = 73.500 p = .562 NS
Wilcoxon’s signed rank post hoc test VER 2 vs. VER 3	Z = −2.384, p = .017*	Z = −1.899, p = .058 NS
VER 4 mean (SD)	1.48 (1.2208)	1.39 (1.2442)	U = 76.000, p = .657 NS
Wilcoxon’s signed rank post hoc test VER 3 vs. VER 4	Z = −2.214, p = .027 NS	Z = −2.539, p = .011*
Friedman’s test a priori for repeated measures	χ^2(3) = 11.792, p = .008*	χ ^2(3) = 10.156, p = .017*

Group comparisons were made at each time point with Mann–Whitney U tests. All significance testing has been Bonferroni corrected. Statistically significant results p<.025 are marked with *.

Table 3. Aggregated group results, explaining changes to self-evaluated scores of vocal effort with within-subject standard deviation (WSSD, see Table 2) taken into account at four time points: VER 1–4.

Repeated measures standardised scores with WSSD	Reading	SOVTE	Mann–Whitney U post hoc test reading vs. SOVTE
WSSD by group	.25	.39	U = 39.000, p = .399 NS
ΔVER 1	0	0	NA
ΔVER 2	2.23	2.30	U = 75.500, p = .643 NS
Wilcoxon’s signed rank post hoc test VER 1 vs. VER 2	Z = −3.065, p = .002*	Z = −3.063, p = .002*
ΔVER 3	3.41	3.50	U = 71.500, p = .504 NS
Wilcoxon’s signed rank post hoc test VER 2 vs. VER 3	Z = −2.524, p = .012*	Z = −1.993, p = .046 NS
ΔVER 4	2.04	1.86	U = 79.500, p = .801 NS
Wilcoxon’s signed rank post hoc test VER 3 vs. VER 4	Z = −2.201, p = .028 NS	Z = −2.521, p = .012*
Friedman’s test a priori for repeated measures	χ^2 = 30.360, p < .001*	χ^2 = 27.440, p < .001*

Time points are compared in total within groups with Friedman’s test for repeated measures as well as at each time change with Wilcoxon’s signed rank test. Group comparisons were made at each time point with Mann–Whitney U tests. All significance testing has been Bonferroni corrected. Statistically significant results p<.025 are marked with *.

van Leer E, van Mersbergen M. Using the Borg CR10 physical exertion scale to measure patient-perceived vocal effort pre and post treatment. J Voice. 2017;31(3):389.e19–389.e25.

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