Measurements of Lower-limb Isometric Single-joint Maximal Voluntary Torque and Rate of Torque Development Capacity Offer Limited Insight into Vertical Jumping Performance

Figures & data

Figure 1. Isometric maximal voluntary contractions as performed for assessment of hip flexors (a), hip extensors (b), hip adductors and abductors (c), trunk extension (d), trunk flexion (e), trunk lateral flexion (f), ankle flexion and extension (g and h) and knee flexion and extension (i).

Table 1. Descriptive statistics and intra-session reliability for all outcome variables

Outcome variable	Mean	SD	Min	Max	ICC	TE (%)
SJ Height (cm)	29.33	5.06	13.00	40.60	0.88	8.02
CMJ Height (cm)	31.68	4.77	17.80	42.70	0.92	4.05
SLCMJ Height (cm)	15.43	3.25	7.60	23.60	0.91	9.80
Knee EXT – Peak torque (Nm/kg)	5.74	1.33	3.32	10.34	0.92	6.1
Knee EXT – RTD100 (Nm/kg/s)	29.42	9.13	5.80	54.07	0.77	12.2
Knee EXT – RTD200 (Nm/kg/s)	23.22	8.11	4.33	32.21	0.81	9.7
Knee FLX – Peak torque (Nm/kg)	3.44	0.62	1.84	5.35	0.84	9.42
Knee FLX – RTD100 (Nm/kg/s)	15.93	5.39	4.24	32.22	0.81	16.5
Knee FLX – RTD200 (Nm/kg)	12.41	2.87	4.93	19.26	0.72	13.2
Ankle EXT – Peak torque (Nm/kg)	4.37	0.98	2.12	7.01	0.95	4.12
Ankle EXT – RTD100 (Nm/kg/s)	19.05	5.95	2.91	31.49	0.64	26.6
Ankle EXT – RTD200 (Nm/kg/s)	16.21	4.09	6.40	26.71	0.75	11.7
Ankle FLX – Peak torque (Nm/kg)	1.36	0.26	0.72	2.10	0.96	3.83
Ankle FLX – RTD100 (Nm/kg/s)	7.45	1.86	2.15	13.29	0.74	10.8
Ankle FLX – RTD200 (Nm/kg/s)	5.48	1.20	2.38	9.20	0.82	8.71
Hip EXT – Peak torque (Nm/kg)	5.06	1.14	2.02	8.05	0.91	6.63
Hip EXT – RTD100 (Nm/kg/s)	17.44	7.88	3.80	35.99	0.95	16.8
Hip EXT – RTD200 (Nm/kg/s)	14.91	4.19	5.39	25.26	0.78	14.1
Hip FLX – Peak torque (Nm/kg)	4.03	0.68	2.50	6.16	0.94	6.22
Hip FLX – RTD100 (Nm/kg/s)	14.60	7.10	2.26	32.37	0.84	15.6
Hip FLX – RTD200 (Nm/kg/s)	10.43	2.65	4.83	17.36	0.86	9.55
Hip ABD – Peak torque (Nm/kg)	2.05	0.28	1.42	2.68	0.93	7.73
Hip ABD – RTD100 (Nm/kg/s)	8.10	3.41	1.77	16.98	0.78	17.1
Hip ABD – RTD200 (Nm/kg/s)	6.92	1.30	4.22	9.93	0.76	9.94
Hip ADD – Peak torque (Nm/kg)	2.25	0.41	1.14	3.70	0.95	4.93
Hip ADD – RTD100 (Nm/kg/s)	9.95	4.63	1.83	22.16	0.73	16.1
Hip ADD – RTD200 (Nm/kg/s)	7.46	1.94	2.83	12.87	0.75	12.6
Trunk EXT – Peak Torque (Nm/kg)	4.18	0.95	1.47	7.83	0.88	7.23
Trunk FLX – Peak Torque (Nm/kg)	3.07	0.67	1.16	5.30	0.93	5.81
Trunk LFLX – Peak Torque (Nm/kg)	2.75	0.73	0.85	7.03	0.85	9.31

SJ – squat jump; CMJ – counter-movement jump; SLCMJ – single-leg countermovement jump; EXT – extension; FLX – flexion; ABD – abduction; ADD – adduction; RTD – rate of torque development;

Table 2. Pearson correlation coefficients among the height of the three jump types and all torque/RFD outcome variables

Outcome variable	SJ Height (cm)	CMJ Height (cm)	SLCMJ Height (cm)
Knee EXT – Peak torque	.312**	.365**	.244**
Knee EXT – RTD100	.147	.227*	.218*
Knee EXT – RTD200	.312**	.292*	.265*
Knee FLX – Peak torque	.337**	.334**	.162
Knee FLX – RTD100	.074	.109	.08
Knee FLX – RTD200	.166	.187*	.147
Ankle EXT – Peak torque	.349**	.312**	.353**
Ankle EXT – RTD100	.255**	.336**	.347**
Ankle EXT – RTD200	.294**	.312**	.342**
Ankle FLX – Peak torque	.236*	.209*	.171
Ankle FLX – RTD100	.183	.217*	.117
Ankle FLX – RTD200	.206*	.206*	.101
Hip EXT – Peak torque	.496**	.437**	.321**
Hip EXT – RTD100	.158	.185	.164
Hip EXT – RTD200	.341**	.300**	.214*
Hip FLX – Peak torque	.349**	.255**	.292**
Hip FLX – RTD100	.094	.104	.164
Hip FLX – RTD200	.215*	.186*	.254**
Hip ABD – Peak torque	.355**	.432**	.304**
Hip ABD – RTD100	.079	.121	.055
Hip ABD – RTD200	.243**	.285**	.202*
Hip ADD – Peak torque	.241*	.341**	.304**
Hip ADD – RTD100	.074	.123	.100
Hip ADD – RTD200	.200*	.288**	.288**
Trunk EXT – Peak Torque	.359**	.330**	.280**
Trunk FLX – Peak Torque	.284**	.232*	.17
Trunk LFLX – Peak Torque	.372**	.335**	.174

SJ – squat jump; CMJ – counter-movement jump; SLCMJ – single-leg countermovement jump; EXT – extension; FLX – flexion; ABD – abduction; ADD – adduction; RTD – rate of torque development; Note that for SJ and CMJ, bilateral strength and RFD measures were considered, while unilateral (for the preferred leg only) measures were correlated with SLCMJ. * – p < 0.05; ** p < 0.01

Figure 2. Scatterplots depicting the relationship between squat jump heights and single-joint peak torque outcomes (upper and middle panel), and rate of torque development outcomes (lower panel).

Table 3. Linear regression models for all three jump types

Jump type/Predictor variables	Regression coefficients				Statistical sig.
SJ height	Adjusted R^2	B	Std. Error	Beta	t	Sig.
Hip EXT – Peak torque	0.278	0.018	0.004	0.403	4.311	0.001
Ankle EXT – RTD200	0.309	0.003	0.001	0.203	2.449	0.016
Trunk LFLX – Peak torque	0.334	0.014	0.006	0.198	2.154	0.034
CMJ height	Adjusted R^2	B	Std. Error	Beta	t	Sig.
Ankle EXT – RTD100	0.223	0.011	0.004	0.26	2.635	0.010
Ankle EXT – RTD200	0.299	0.002	0.001	0.273	3.383	0.001
Hip ABD – Peak torque	0.338	0.039	0.015	0.232	2.582	0.011
Trunk LFLX – Peak torque	0.359	0.012	0.006	0.187	2.075	0.041
SLCMJ Height	Adjusted R^2	B	Std. Error	Beta	t	Sig.
Ankle EXT – Peak torque	0.141	0.014	0.008	0.184	1.801	0.075
Hip EXT – Peak torque	0.203	0.017	0.005	0.297	3.25	0.002
Ankle EXT – RTD100	0.245	0.003	0.001	0.246	2.533	0.013

SJ – squat jump; CMJ – counter-movement jump; SLCMJ – single-leg countermovement jump; EXT – extension; FLX – flexion; ABD – abduction; ADD – adduction; RTD – rate of torque development; Note that for prediction of SJ and CMJ height, bilateral strength and RFD measures were entered into the regression, while unilateral (for the preferred leg only) measures were enter into the regression for SLCMJ, height prediction. Trunk measures were entered into all models.