Variability of lumbar spinal alignment among power- and weightlifters during the deadlift and barbell back squat

Figures & data

Table 1. Participant characteristics (mean±SD)

Participants	Age (y)	Mass (kg)	Height (m)	Experience (y)*	Squat 1RM (kg)^†	Deadlift 1RM (kg)^†
All (n = 24)	25 ± 5	81 ± 1	1.71 ± 0.07	8 ± 6	134 ± 42	162 ± 56
Powerlifters (n = 14)	26 ± 4	84 ± 8	1.73 ± 0.06	8 ± 5	148 ± 42	180 ± 51
Men (n = 10)	27 ± 5	86 ± 7	1.76 ± 0.04	9 ± 5	165 ± 29	201 ± 40
Women (n = 4)	25 ± 1	78 ± 6	1.66 ± 0.04	5 ± 2	90 ± 23	130 ± 40
Weightlifters (n = 10)	24 ± 7	76 ± 1	1.69 ± 0.08	7 ± 8	118 ± 37	138 ± 54
Men (n = 4)	28 ± 1	82 ± 2	1.73 ± 0.08	12 ± 1	158 ± 19	189 ± 51
Women (n = 6)	22 ± 3	71 ± 9	1.67 ± 0.08	5 ± 2	91 ± 10	103 ± 14

*Strength training experience; ^†Self-estimated one-repetition maximum (1RM)

Figure 1. Three calibrated IMUs were affixed at the level of the Processus spinosus at Th11 and L2, and at Sacrum (S2). This file/figure is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.

Table 2. Deadlift: The ICC values for the variables start position, minimum [min] angle, maximum [max] angle and range of motion [ROM] that were chosen to quantify the movement patterns in the upper (thoracolumbar) and lower (lumbopelvic) lumbar areas in all lifters (n = 24) and separately for the powerlifters (n = 14) and weightlifters (n = 10)

	Thoracolumbar region			Lumbopelvic region
	Sagittal plane	Frontal plane	Horizontal plane	Sagittal plane	Frontal plane	Horizontal plane
Start position
All lifters	0.98 (0.97–0.99)	0.97 (0.95–0.99)	0.89 (0.81–0.95)	0.97 (0.94–0.99)	0.99 (0.97–0.99)	0.94 (0.89–0.97)
Powerlifters	1.00 (0.99–1.00)	0.97 (0.93–0.99)	0.93 (0.85–0.98)	0.98 (0.95–0.99)	0.99 (0.97–1.00)	0.94 (0.87–0.98)
Weightlifters	0.97 (0.91–0.99)	0.98 (0.94–0.99)	0.84 (0.61–0.95)	0.95 (0.85–0.99)	0.98 (0.89–1.00)	0.95 ()0.86–0.99
Min angle
All	0.99 (0.97–0.99)	0.97 (0.94–0.98)	0.72 (0.54–0.86)	0.98 (0.96–0.99)	0.98 (0.96–0.99)	0.94 (0.89–0.97)
Powerlifters	0.99 (0.99–1.00)	0.97 (0.92–0.99)	0.62 (0.32–0.84)	0.98 (0.96–0.99)	0.97 (0.93–0.99)	0.95 (0.89–0.98)
Weightlifters	0.96 (0.90–0.99)	0.97 (0.91–0.99)	0.80 (0.54–0.94)	0.97 (0.92–0.99)	0.99 (0.97–1.00)	0.93 (0.81–0.98)
Max angle
All	0.95 (0.90–0.98)	0.92 (0.84–0.96)	0.88 (0.78–0.94)	0.97 (0.94–0.99)	0.99 (0.97–0.99)	0.88 (0.78–0.94)
Powerlifters	0.93 (0.84–0.98)	0.90 (0.78–0.96)	0.89 (0.76–0.96)	0.97 (0.93–0.99)	0.99 (0.97–1.00)	0.84 (0.66–0.94)
Weightlifters	0.97 (0.92–0.99)	0.96 (0.86–0.99)	0.87 (0.67–0.96)	0.95 (0.88–0.99)	0.98 (0.94–1.00)	0.91 (0.77–0.98)
ROM
All	0.87 (0.77–0.94)	0.84 (0.72–0.92)	0.69 (0.50–0.84)	0.95 (0.90–0.98)	0.92 (0.85–0.96)	0.83 (0.69–0.91)
Powerlifters	0.82 (0.63–0.93)	0.62 (0.33–0.84)	0.66 (0.39–0.87)	0.96 (0.90–0.99)	0.93 (0.84–0.97)	0.81 (0.62–0.93)
Weightlifters	0.93 (0.81–0.98)	0.96 (0.89–0.99)	0.77 (0.49–0.93)	0.93 (0.82–0.98)	0.91 (0.76–0.97)	0.85 (0.64–0.96)

Table 3. Squat: The ICC values for the variables start position, minimum [min] angle, maximum [max] angle and range of motion [ROM] that were chosen to quantify the movement patterns in the upper (thoracolumbar) and lower (lumbopelvic) lumbar areas in all lifters (n = 23) and separately for the powerlifters (n = 13) and weightlifters (n = 10)

	Thoracolumbar region			Lumbopelvic region
	Sagittal plane	Frontal plane	Horizontal plane	Sagittal plane	Frontal plane	Horizontal plane
Start position
All	0.96 (0.91–0.98)	0.96 (0.92–0.98)	0.91 (0.83–0.96)	0.96 (0.92–0.98)	0.99 (0.98–0.99)	0.80 (0.63–0.91)
Powerlifters	0.96 (0.89–0.99)	0.98 (0.94–0.99)	0.94 (0.87–0.98)	0.96 (0.91–0.99)	0.99 (0.98–1.00)	0.81 (0.60–0.93)
Weightlifters	0.96 (0.88–0.99)	0.91 (0.78–0.98)	0.77 (0.49–0.93)	0.90 (0.73–0.97)	0.98 (0.93–0.99)	0.78 (0.47–0.93)
Min angle
All	0.99 (0.99–1.00)	0.98 (0.96–0.99)	0.95 (0.89–0.98)	0.99 (0.99–1.00)	0.98 (0.97–0.99)	0.95 (0.90–0.98)
Powerlifters	0.99 (0.99–1.00)	0.99 (0.96–1.00)	0.97 (0.93–0.99)	1.00 (0.99–1.00)	0.98 (0.96–0.99)	0.96 (0.91–0.99)
Weightlifters	0.99 (0.98–1.00)	0.96 (0.90–0.99)	0.86 (0.66–0.96)	0.99 (0.97–1.00)	0.98 (0.96–1.00)	0.86 (0.65–0.96)
Max angle
All	0.98 (0.95–0.99)	0.98 (0.95–0.99)	0.93 (0.86–0.97)	0.96 (0.92–0.98)	0.99 (0.99–1.00)	0.91 (0.83–0.96)
Powerlifters	0.98 (0.94–0.99)	0.99 (0.96–1.00)	0.96 (0.90–0.99)	0.97 (0.93–0.99)	0.99 (0.98–1.00)	0.91 (0.79–0.97)
Weightlifters	0.98 (0.94–0.99)	0.95 (0.85–0.99)	0.82 (0.58–0.95)	0.92 (0.78–0.98)	0.99 (0.97–1.00)	0.93 (0.82–0.98)
ROM
All	0.82 (0.68–0.91)	0.93 (0.88–0.97)	0.86 (0.74–0.93)	0.86 (0.75–0.93)	0.78 (0.61–0.89)	0.83 (0.70–0.92)
Powerlifters	0.78 (0.54–0.92)	0.95 (0.87–0.98)	0.95 (0.88–0.98)	0.93 (0.84–0.98)	0.81 (0.61–0.32)	0.88 (0.74–0.96)
Weightlifters	0.88 (0.70–0.97)	0.92 (0.79–0.98)	0.63 (0.29–0.88)	0.82 (0.59–0.95)	0.73 (0.40–0.91)	0.77 (0.48–0.93)

Table 4. The minimum detectable change for the variables start position, minimum [min] angle, maximum [max] angle and range of motion [ROM] in degrees [°] that were chosen to quantify spinal alignment in the upper (thoracolumbar) and lower (lumbopelvic) lumbar spinal areas in all lifters

	Thoracolumbar region			Lumbopelvic region
	Sagittal plane	Frontal plane	Horizontal plane	Sagittal plane	Frontal plane	Horizontal plane
Deadlift (N = 24)
Start position	3	2	2	.7	2	2
Min angle	2	2	3	3	1	2
Max angle	8	2	2	5	1	2
ROM	8	3	2	4	1	2
Squat (N = 23)
Start position	6	2	2	5	2	3
Min angle	2	2	2	2	2	2
Max angle	4	1	2	4	1	2
ROM	4	1	2	5	2	2

Table 5. The three-dimensional angles (SegAng) in degrees [°] of the upper lumbar spine (thoracolumbar region) during the deadlift for the Start position, Stop position, Minimum (Min) angle, Maximum (Max) angle and range of motion (ROM) as well as results of the two-way factorial-repeated measures ANOVA (within-participants effect) in all lifters (n = 24) and separately for the powerlifters (n = 14) and weightlifters (n = 10)

						Within-participants effect SegAng*group		Within-participants effect SegAng
	SegAng Start [°]	SegAng Stop [°]	Min SegAng [°]	Max SegAng [°]	ROM [°]	P	Partial Eta Squared	P	Partial Eta Squared
All
Sagittal plane^†	4.6 ± 7.5	13.0 ± 11.5^#	2.2 ± 6.6^#	14.0 ± 11.8^#	11.8 ± 7.3	0.636	0.012	<0.001	0.671
Frontal plane	−1.8 ± 4.8	−0.4 ± 2.4	−3.3 ± 4.3^#	1.0 ± 2.7^#	4.3 ± 2.7	0.171	0.081	<0.001	0.471
Horizontal plane	0.3 ± 2.2	−0.8 ± 2.0	−1.9 ± 2.0^#	1.5 ± 2.0^#	3.4 ± 1.4	0.458	0.033	<0.001	0.646
Powerlifters
Sagittal plane^†	3.5 ± 7.8	12.7 ± 10.9	1.9 ± 7.5	13.4 ± 10.9	11.5 ± 6.5
Frontal plane	−2.9 ± 4.6	−0.3 ± 2.8	−3.8 ± 4.2	0.5 ± 3.0	4.3 ± 1.8
Horizontal plane	0.2 ± 2.3	−1.0 ± 1.8	−2.4 ± 1.7	1.2 ± 2.0	3.6 ± 1.5
Weightlifters
Sagittal plane^†	6.1 ± 7.1	13.3 ± 12.9	2.8 ± 5.5	14.9 ± 13.4	12.1 ± 8.7
Frontal plane	−0.2 ± 4.8	−0.5 ± 1.8	−2.6 ± 4.5	1.6 ± 2.3	4.2 ± 3.6
Horizontal plane	0.3 ± 2.1	−0.4 ± 2.4	−1.3 ± 2.3	2.0 ± 2.0	3.2 ± 1.3

^†A positive sagittal plane angle indicated a lordotic spinal alignment and negative sagittal plane angle indicated a kyphotic spinal alignment

^#Significant difference to Start position after adjustment for multiple comparisons using the Bonferroni correction

Table 6. The three-dimensional angles (SegAng) in degrees [°] of the lower lumbar spine (lumbopelvic region) during the deadlift for the Start position, Stop position, Minimum (Min) angle, Maximum (Max) angle and range of motion (ROM) as well as results of the two-way factorial-repeated measures ANOVA (within-participants effect) in all lifters (n = 24) and separately for the powerlifters (n = 14) and weightlifters (n = 10)

						Within-participants effect SegAng*group		Within-participants effect SegAng
	SegAng Start [°]	SegAng Stop [°]	Min SegAng [°]	Max SegAng [°]	ROM [°]	P	Partial Eta Squared	P	Partial Eta Squared
All
Sagittal plane^†	−3.7 ± 7.4	16.2 ± 9.3^#	−4.7 ± 7.5^#	17.0 ± 9.2^#	21.7 ± 6.4	0.787	0.004	<0.001	0.913
Frontal plane	2.2 ± 4.4	1.9 ± 3.2	0.6 ± 3.4^#	3.4 ± 3.7^#	2.8 ± 1.7	0.449	0.034	<0.001	0.444
Horizontal plane	−0.2 ± 2.6	0.2 ± 1.9	−1.4 ± 2.2^#	1.4 ± 2.0^#	2.8 ± 1.3	0.812	0.006	<0.001	0.545
Powerlifters
Sagittal plane^†	−6.1 ± 6.8	13.8 ± 10.1	−6.7 ± 6.6	14.6 ± 9.7	21.3 ± 7.1
Frontal plane	2.0 ± 4.8	1.3 ± 3.1	0.2 ± 3.4	3.2 ± 4.2	3.1 ± 1.9
Horizontal plane	−0.2 ± 2.6	0.1 ± 1.6	−1.5 ± 2.2	1.3 ± 1.6	2.8 ± 1.3
Weightlifters
Sagittal plane^†	−0.3 ± 7.2	19.5 ± 7.1	−1.9 ± 8.0	20.4 ± 7.7	22.3 ± 5.6
Frontal plane	2.5 ± 3.8	2.7 ± 3.2	1.3 ± 3.5	3.7 ± 3.2	2.4 ± 1.2
Horizontal plane	−0.3 ± 2.8	0.4 ± 2.3	−1.3 ± 2.3	1.5 ± 2.6	2.8 ± 1.5

^†A positive sagittal plane angle indicated a lordotic spinal alignment and negative sagittal plane angle indicated a kyphotic spinal alignment.

^#Significant difference to Start position after adjustment for multiple comparisons using the Bonferroni correction.

Table 7. The three-dimensional angles (SegAng) in degrees [°] of the upper lumbar spine (thoracolumbar region) during the squat for the Start position, Minimum (Min) angle, Maximum (Max) angle and range of motion (ROM) as well as results of the two-way factorial-repeated measures ANOVA (within-participants effect) in all lifters (n = 24) and separately for the powerlifters (n = 13) and weightlifters (n = 10)

					Within-participants effect SegAng*group		Within-participants effect SegAng
	Start SegAng [°]	Min angle SegAng [°]	Max SegAng [°]	ROM [°]	P	Partial Eta Squared	P	Partial Eta Squared
All
Sagittal plane^†	7.8 ± 9.8	4.0 ± 7.7^#	13.7 ± 9.5^#	9.7 ± 3.3	0.593	0.025	<0.001	0.799
Frontal plane	0.3 ± 3.1	−1.9 ± 4.1^#	1.7 ± 3.3^#	3.6 ± 2.0	0.939	0.001	<0.001	0.634
Horizontal plane	−0.3 ± 2.9	−2.2 ± 2.7^#	1.5 ± 2.3^#	3.7 ± 1.5	0.630	0.022	<0.001	0.762
Powerlifters
Sagittal plane^†	6.6 ± 11.5	3.2 ± 8.8	12.2 ± 10.5	9.0 ± 3.2
Frontal plane	−0.1 ± 3.4	−2.4 ± 4.9	1.3 ± 3.8	3.7 ± 2.2
Horizontal plane	−0.8 ± 3.4	−2.5 ± 3.1	1.3 ± 2.7	3.8 ± 1.7
Weightlifters
Sagittal plane^†	9.5 ± 7.0	5.1 ± 6.3	15.6 ± 7.8	10.6 ± 3.1
Frontal plane	0.8 ± 2.5	−1.3 ± 2.9	2.3 ± 2.5	3.6 ± 1.8
Horizontal plane	0.2 ± 1.9	−1.8 ± 1.9	1.7 ± 1.7	3.5 ± 1.2

^†A positive sagittal plane angle indicated a lordotic spinal alignment and negative sagittal plane angle indicated a kyphotic spinal alignment.

^#Significant difference to Start position after adjustment for multiple comparisons using the Bonferroni correction.

Table 8. The three-dimensional angles (SegAng) in degrees [°] of the lower lumbar spine (lumbopelvic region) during the squat for the Start position, Minimum (Min) angle, Maximum (Max) angle and range of motion (ROM) as well as results of the two-way factorial-repeated measures ANOVA (within-participants effect) in all lifters (n = 24) and separately for the powerlifters (n = 13) and weightlifters (n = 10)

					Within-participants effect SegAng*group		Within-participants effect SegAng
	Start SegAng [°]	Min angle SegAng [°]	Max SegAng [°]	ROM [°]	P	Partial Eta Squared	P	Partial Eta Squared
All
Sagittal plane^†	12.2 ± 8.9	−4.5 ± 7.9^#	13.6 ± 8.4^#	18.1 ± 4.9	0.336	0.047	<0.001	0.921
Frontal plane	0.2 ± 4.7	−1.8 ± 4.6^#	1.3 ± 4.7^#	3.1 ± 1.2	0.759	0.009	<0.001	0.796
Horizontal plane	−0.8 ± 2.4	−2.6 ± 2.4^#	0.8 ± 2.1^#	3.5 ± 1.3	0.315	0.054	<0.001	0.829
Powerlifters
Sagittal plane^†	7.3 ± 6.8	−8.2 ± 6.0	9.1 ± 6.2	17.4 ± 4.0
Frontal plane	0.4 ± 5.7	−1.5 ± 5.1	1.5 ± 5.5	3.0 ± 1.3
Horizontal plane	−1.0 ± 2.9	−2.6 ± 3.0	0.6 ± 2.3	3.2 ± 1.3
Weightlifters
Sagittal plane^†	18.5 ± 7.2	0.3 ± 7.5	19.5 ± 7.2	19.2 ± 5.8
Frontal plane	−0.0 ± 3.2	−2.2 ± 4.0	1.1 ± 3.7	3.3 ± 1.1
Horizontal plane	−0.5 ± 1.7	−2.8 ± 1.3	1.1 ± 1.6	3.8 ± 1.3

^†A positive sagittal plane angle indicated a lordotic spinal alignment and negative sagittal plane angle indicated a kyphotic spinal alignment.

^#Significant difference to Start position after adjustment for multiple comparisons using the Bonferroni correction.