A Role for Trunk Function in Elite Recumbent Handcycling Performance?

Figures & data

Table 1. Number of time-trial results included in the analysis per sex and spinal cord injury level group

SCI level groups	Time trials
	Women				Men				Total
	Age^a	AIS A/B^b	AIS C/D^c	Total	Age^a	AIS A/B^b	AIS C/D^c	Total
Th1–Th5 (high thoracic)	41 ± 10	17	0	17	42 ± 12	94	2	96	113
Th6–Th9 (upper abdominals)	33 ± 2	2	19	21	35 ± 6	79	16	95	119
Th10–L1 (lower abdominals)	40 ± 11	84	3	87	40 ± 5	132	57	189	277
≤L2 (full trunk)	26 ± 3	4	5	9	33 ± 11	0	10	10	19
Total		107	27	134		305	85	390	524^d

^aAveraged age and standard deviation of the group

^bAIS A or B, equivalent to complete motor lesion

^cAIS C or D, equivalent to incomplete motor lesion

^dThere are 4 additional participants not included in this table due to missing data regarding AIS. The total sample is representative of 81 unique handcycling athletes (64 males, 17 females).

Figure 1. Handheld dynamometer device (MicroFET2 ProCare) (left), and position of the athlete during trunk flexion test (right)

Table 2. Multilevel models (Levels: Event and Athlete) assessing the differences in average time-trial velocity among pairs of SCI groups, with Th1–Th5, Th6–Th9 and Th10–L1 as a reference after controlling for age, sex (male = 1; female = 0), and AIS differences (AIS A/B = 1; AIS C/D = 0). Β = unstandardised beta values; SE = standard error; CI = confidence interval

Model with Th1–Th5 as reference
Fixed effect	β	SE	CI (95%)	z-value	p-value	Cohen’s d
Constant	7.96	0.62	[6.75; 9.17]	12.91	< 0.00001
Th1–Th5:Th6–Th9	0.11	0.32	[−0.51; 0.73]	0.35	0.73	0.02
Th1–Th5:Th10–L1	0.49	0.30	[−0.09; 1.08]	1.66	0.10	0.08
Th1–Th5:≤L2	−0.51	0.56	[−1.60; 0.59]	−0.91	0.36	0.08
Model with Th6–Th9 as reference
Fixed effect	β	SE	CI (95%)	z-value	p-value	Cohen’s d
Constant	8.07	0.58	[6.94; 9.21]	13.97	< 0.00001
Th6–Th9:Th1–Th5	−0.11	0.32	[−0.73; 0.51]	−0.35	0.73	0.02
Th6–Th9:Th10–L1	0.38	0.28	[−0.17; 0.94]	1.36	0.17	0.07
Th6–Th9:≤L2	−0.62	0.53	[−1.66; 0.42]	−1.16	0.25	0.10
Model with Th10–L1 as reference
Fixed effect	β	SE	CI (95%)	z-value	p-value	Cohen’s d
Constant	8.46	0.57	[7.34; 9.57]	14.91	< 0.00001
Th10–L1:Th1–Th5	−0.49	0.30	[−1.08; 0.09]	−1.66	0.10	0.08
Th10–L1:Th6–Th9	−0.38	0.28	[−0.94; 0.17]	−1.36	0.17	0.07
Th10–L1:≤L2	−1.00	0.51	[−2.00; 0]	−1.95	0.051	0.11
Variables Controlled^a
Parameter	β	SE	CI (95%)	z-value	p-value
Sex	1.00	0.28	[0.46; 1.55]	3.60	0.0003
Age	0.003	0.01	[−0.02; 0.03]	0.23	0.82
AIS (motor function)	−0.36	0.31	[−0.96; 0.25]	−1.16	0.25

^aThe values from the controlled variables did not change between models and therefore are presented separately for an easier visualization.

Figure 2. Scatterplot of trunk flexion strength and average time-trial velocity. Data points are identified by sex and by handcycling class. (H3: spinal cord injury with lesion levels between Th1 and Th10; H4 lesion levels below Th11 or amputations)

Figure 3. Scatterplots of trunk flexion strength and handcycling performance during a 20-sec isokinetic sprint: Mean PO (upper graph) and Peak PO (lower graph). data points are identified by sex and by handcycling class. (H3: spinal cord injury with lesion levels between Th1 and Th10; H4 lesion levels below Th11 or amputations)