Age-related changes in shock absorption capacity of the human spinal column

Figures & data

Table 1 Characteristics of assessment groups

Analyzed groups	Number of males/females	Age (years), mean (SD)	Height (cm), mean (SD)	Weight (kg), mean (SD)	BMI (kg/m^2), mean (SD)
Third (n=37)	16/21	24.2 (2.6)	170.1 (9.1)	68.8 (12.3)	23.8 (3.7)
Fifth (n=39)	17/22	46.1 (2.3)	169.5 (8.4)	69.9 (10.9)	24.6 (3.1)
Seventh (n=36)	14/22	64.7 (2.9)	168.2 (8.8)	70.7 (11.4)	25.3 (3.5)

Figure 1 Scheme of vibration platform (a: 2 Hz electrodynamic vibrator; b: 20 Hz electrodynamic vibrator; c: compression springs; d: accelerometer for control; e: plate of platform; f: microcontroller).

Figure 2 Scheme of measurement stand and equipment (a: vibration platform; b: amplifier; c: measuring analog-to-digital card; d: PC; e: analyzed parameters).

Abbreviation: PPA, peak-to-peak amplitude.

Table 2 Values of analyzed parameters and statistical differences between particular decades of life

Analyzed groups	VMS (V), mean ±SD		PPA (V), mean ±SD		F2 (V^2/Hz), mean ±SD		F20 (V^2/Hz), mean ±SD
	Sacrum	Occiput	Sacrum	Occiput	Sacrum	Occiput	Sacrum	Occiput
Third (20–29)	0.64±0.31	0.21±0.13	1.42±1.53	0.91±0.64	1.62±0.82	1.57±0.82	11.47±5.02	2.43±1.93
Fifth (40–49)	0.66±0.35	0.21±0.14	1.47±1.62	0.98±0.73	1.64±0.79	1.58±0.87	12.51±6.14	5.02±3.61
Seventh (60–69)	0.71±0.42	0.23±0.18	1.58±1.64	1.14±0.70	1.65±0.96	1.60±1.14	13.03±7.66	10.84±5.12
p-values
Third vs fifth	0.143	0.387	0.397	0.114	0.190	0.485	0.093	0.012
Third vs seventh	0.052	0.178	0.060	0.037	0.398	0.217	0.051	0.001
Fifth vs seventh	0.196	0.215	0.105	0.092	0.264	0.269	0.127	0.006

Note: Bold values are statistically significant (p<0.05).

Abbreviation: PPA, peak-to-peak amplitude.

Figure 3 Course of the signals registered on the S2 level: representatives for individuals in the third decade of life (A), fifth decade of life (B), and seventh decade of life (C). Course of the signals registered on the C0 level: representatives for individuals in the third decade of life (D), fifth decade of life (E), and seventh decade of life (F).

Figure 4 Power spectrum distribution in all signals recorded from the C0 level for particular age groups.