Differences in kinematics and driver performance in elite female and male golfers

Figures & data

Table 1. Placement of magnetic sensors and landmarks used to construct the segments in the anatomical alignment

Local reference frame	Sensor placement	Landmarks used for anatomical alignment	Defined joint coordinate system
Club	Below Grip	Top of grip. Anterior and posterior middle handle/grip. Anterior and posterior Hozel. Club head, bottom groove at heel. Club head, bottom grove at toe. Club head, top groove at toe.	Mid-point between anterior mid-handle and posterior mid-handle (origin). Line between Mid-point, anterior mid-handle and posterior mid-handle and hozel (y vector). Line perpendicular to the plane formed by the Y-axis (Z vector). Common line perpendicular to the Z and X axis, pointing forward (X-vector).
Left hand		Point directly inferior of the styloid process of the ulna Point directly inferior of the styloid process of the radius 2^nd metacarpal 5^th metacarpal	Mid-point between point directly inferior of the styloid process of the ulna and point directly inferior of the styloid process of the radius (origin). Line between point directly inferior of the styloid process of the ulna and point directly inferior of the styloid process of the radius process (Y vector). Line perpendicular to the plane formed by the Y-axis (Z vector). Common line perpendicular to the Z and X axis, pointing forward (X-vector).
Left arm	Posterior upper arm	Left acromion process. Lateral epicondyle Medial epicondyle.	Acromion process (origin). Line connecting acromioclavicular to mid-point between lateral epicondyle and medial epicondyle pointing to the glenohumeral (Y vector). Line perpendicular to the plane formed by the Y-axis (Z vector). Common line perpendicular to the Z and X axis, pointing forward (X-vector).
Thorax	On T5	Left Acromioclavicular process. Right Acromioclavicular process. Right side mid-axillary line thorax, high. Right side mid-axillary line thorax, low	Mid-point between left and right acromioclavicular joint (origin). Line between left and right acromioclavicular process (Y vector). Line perpendicular to the plane formed by the Y-axis (Z vector). Common line perpendicular to the Z and X axis, pointing forward (X-vector).
Pelvis	Sacrum	Superior point left greater trochanter. Superior point right greater trochanter. point several inches above the trochanter point and aligned to be parallel with a visualised line from the left PSIS to the pubic symphysis	Mid-point of the left and right greater trochanter (origin). Line between left and right greater trochanter (Z vector). Line between the origin and point midway between left PSOS and pubic symphysis, parallel to the estimated pelvis tilt (Y vector). Common line perpendicular to the Z and X axis, pointing forward (X-vector).

Table 2. Definition of kinematic variables

Variable	Description
Golf position
Address	The address sample was determined by searching backwards through the shaft angular speed curve, from 0.1 sec before top, to the first sample that is less than 10 d/s.
TOB	Determinted as the point of lowest angular velocity of the club shaft between backswing and impact.
Impact	The sample prior to when the clubhead reaches the position on the X-axis equivalent to where it was at address.
Displacement
Thorax lift	Vertical displacement of the origin of the thorax segment
Thorax sway	Horizontal, medial-lateral, displacement of the origin of the thorax segment
Thorax thrust	Horizontal, anterior-posterior, displacement of the origin of the thorax segment
Pelvis Lift (cm)	Vertical displacement of the origin of the pelvis segment
Pelvis sway	Horizontal, medial-lateral, displacement of the origin of the pelvis segment
Pelvis thrust	Horizontal, anterior-posterior, displacement of the origin of the pelvis segment
Translational
Wrist set (°)	The angle of the left forearm with respect to a Z-vector
Wrist stretch (°)	The change in amplitude between wrist angle TOB and smallest wrist angle reached during the downswing
Shoulder adduction (°)	The angle of the humerus with respect to thorax and is measured around the local X-axis of the shoulder
Minimum shoulder adduction (°)	The smallest value of shoulder adduction during the downswing
Shoulder stretch (°)	The change in amplitude of between shoulder adduction TOB and smallest shoulder adduction reached during the downswing
Thorax rotation (°)	Rotation of the thorax around its local Y-axis
Thorax lateral bend (°)	Rotation of the thorax around its local X-axis
Thorax flexion (°)	Rotation of the thorax around its local Z-axis
Spine rotation (°)	Pelvis rotation subtracted from thorax rotation
Spine lateral flexion (°)	Pelvis lateral bend subtracted from thorax lateral bend
Spine flexion (°)	Pelvis flexion subtracted from thorax flexion
Spine rotation TOB (°)	The maximum value of spine rotation during the downswing
X-factor (°)	The amplitude of spine rotation at TOB
X-factor stretch (°)	The change in amplitude of between X-factor and the greatest spine rotation reached during the downswing
Pelvis rotation (°)	Rotation of the pelvis around its local Y-axis
Pelvis lateral bend (°)	Rotation of the pelvis around its local X- axis
Pelvis flexion (°)	Rotation of the pelvis around its local Z-axis
Temporal
Wrist speed (ω)	The resultant angular velocity, from all three rotation vectors
Arm peak speed (ω)	The resultant angular velocity, from all three rotation vectors
Thorax peak speed(ω)	The resultant angular velocity, from all three rotation vectors
Pelvis peak speed(ω)	The resultant angular velocity, from all three rotation vectors

Table 3. Bayesian T-tests for kinematic differences between women and men

	Group	Mean	SD	BF₁₀	error %
Driver Performance
Carry distance (m)	Women	185.8	20.6	822.44**	1.870e -6
	Men	233.6	16.3
CHS (m/s)	Women	41.5	2.2	2.036e +6**	2.461e -9
	Men	50.8	1.7
Displacement
Thorax sway TOB (cm)	Women	−1.5	2.9	0.49	1.062e -4
	Men	−0.4	3.5
Thorax thrust TOB (cm)	Women	5.9	2.7	0.45	7.419e -5
	Men	5.2	2.7
Thorax lift TOB (cm)	Women	−3.7	3.4	0.47	5.838e -6
	Men	−4.7	2.5
Thorax sway BI (cm)	Women	0.9	5.8	0.7	0.01
	Men	−2.4	5.9
Thorax thrust BI (cm)	Women	0.2	3.1	0.54	0.01
	Men	−1.2	3.4
Thorax Lift BI (cm)	Women	1.9	3.9	0.47	6.327e -6
	Men	3.2	4.7
Pelvis sway TOB (cm)	Women	−0.7	4.2	0.42	5.021e -5
	Men	−0.05	2.3
Pelvis thrust TOB (cm)	Women	4.0	2.3	0.53	0.01
	Men	3.1	2.6
Pelvis lift TOB (cm)	Women	−3.3	1.1	0.40	5.751e -6
	Men	−3.2	1.6
Pelvis sway BI (cm)	Women	7.5	3.2	1.64	4.074e -4
	Men	10.3	2.6
Pelvis thrust BI (cm)	Women	5.4	3.0	0.40	4.850e -6
	Men	5.5	3.0
Pelvis lift BI (cm)	Women	3.0	2.8	0.40	3.238e -6
	Men	2.8	3.6
Translational
Wrist set TOB (°)	Women	92.8	10.4	0.50	2.825e -4
	Men	88.9	11.5
Wrist stretch (°)	Women	7.0	6.9	0.44	8.229e -5
	Men	8.7	6.8
Shoulder adduction TOB (°)	Women	41.2	6.3	0.40	6.754e -6
	Men	41.1	5.8
Shoulder stretch (°)	Women	3.6	3.3	0.40	6.181e -6
	Men	3.7	3.3
Thorax rotation TOB (°)	Women	−100.4	8.0	1.04	0.01
	Men	−92.4	12.6
Thorax rotation BI (°)	Women	28.3	7.9	0.94	0.01
	Men	21.0	12.2
Spine lateral bend TOB (°)	Women	−35.5	8.9	0.90	0.01
	Men	−40.9	6.5
Spine lateral bend BI (°)	Women	25.7	6.5	0.42	5.344e -5
	Men	27.0	7.3
Spine flexion TOB (°)	Women	0.1	15.6	1.17	0.01
	Men	10.7	10.3
Spine flexion BI (°)	Women	−8.3	23.8	0.81	2.550e -4
	Men	−20.1	10.2
Spine rotation TOB (°)	Women	57.8	13.4	0.77	3.025e -4
	Men	51.4	5.8
X-factor stretch (°)	Women	3.8	4.7	0.41	1.745e -5
	Men	3.2	4.0
Pelvis rotation TOB (°)	Women	−42.4	8.7	0.57	0.01
	Men	−38.3	9.5
Pelvis rotation BI (°)	Women	51.3	11.9	1.01	0.01
	Men	41.9	13.5
Temporal
Backswing time (s)	Women	0.89	0.13	0.41	1.371e -5
	Men	0.88	0.17
Downswing time (s)	Women	0.28	0.03	5.21*	7.712e -4
	Men	0.24	0.02
Follow through time (s)	Women	0.73	0.12	0.45	7.333e -5
	Men	0.77	0.12
Time to arm peak speed (s)	Women	0.08	0.01	31.49**	2.927e -4
	Men	0.07	0.01
Time to thorax peak speed (s)	Women	0.08	0.02	0.43	6.643e -5
	Men	0.07	0.02
Time to pelvis peak speed (s)	Women	0.11	0.02	0.61	0.01
	Men	0.09	0.02
Arm peak speed (ω)	Women	969.9	104.9	7.76*	2.740e -5
	Men	1115.3	102.8
Thorax peak speed (ω)	Women	697.0	74.1	0.40	5.816e -6
	Men	699.8	78.0
Pelvis peak speed (ω)	Women	474.2	59.2	0.40	6.231e -6
	Men	476.3	82.4
Wrist peak speed (ω)	Women	1016.8	150.9	20.37**	6.108e -4
	Men	1301.4	190.7
Arm acceleration DS (α)	Women	5101.4	1178.0	5.20*	7.721e -4
	Men	6565.9	1094.9
Thorax acceleration DS (α)	Women	3611.9	928.4	1.00	0.01
	Men	4219.6	702.1
Pelvis acceleration DS (α)	Women	2841.5	566.3	1.38	0.01
	Men	3320.3	542.2

CHS = clubhead speed, CD = carry distance, TOB = top of backswing, DS = downswing, BI = ball impact.

Table 4. Bayesian ANCOVA model explaining variance for clubhead speed for women and men

Models	P(M)	P(incl)	BF 10	BF Inclusion	% error
Model for women
Null model	0.125		1
Participant + wrist peak speed + thorax rotation peak speed	0.125		2.437e +16		1.984
Effects
Participant		0.50		473015.5
Thorax rotation peak speed		0.50		2.118
Wrist peak speed		0.50		1.677
Model for men
Null model	0.031		1
Participant + thorax lift BI +spine flexion BI + thorax thrust TOB + shoulder adduction TOB	0.031		15700.44
Effects
Participant		0.50		54.809
Thorax lift BI		0.50		2.79
Spine flexion BI		0.50		2.306
Thorax thrust TOB		0.50		19.551
Shoulder adduction TOB		0.50		0.84

TOB = top of backswing, DS = downswing, BI = ball impact.

Table 5. Bayesian ANCOVA model explaining variance for carry for women and men

Models	P(M)	P(incl)	BF 10	BF Inclusion	% error
Model for women
Null model	0.031		1
Arm peak speed + Wrist set TOB + Thorax rotation TOB + Pelvis lift TOB + Trunk lateral bend BI	0.031		3.497e +7
Effects
Arm peak speed		0.500		561.811
Wrist set TOB		0.500		29.695
Thorax rotation TOB		0.500		1.387
Pelvis lift TOB		0.500		2.378
Trunk lateral bend BI		0.500		3691.915
Model for men
Null model	0.031		1
X-factor stretch + Wrist peak speed + pelvis acceleration + pelvis peak speed	0.031		5.555e +8		8.205e -5
Effects
X-factor stretch		0.50		7.45
Wrist peak speed		0.50		14.60
Pelvis acceleration		0.50		12.63
Pelvis peak speed		0.50		75.26

TOB = top of backswing, DS = downswing, BI = ball impact.