Ground reaction forces and back

injuries to fast bowlers in cricket

Overview of the presentation

• Epidemiology of back pain in fast bowlers

• Current fast bowling techniques and issues

• Influence of ground reaction forces on back pain

• Analysis of relevant research and their findings

• Future direction of research

• Conclusion

Epidemiology of back pain in fast bowlers

Why do back injuries get so much attention?

• Alarming that LBP is rising in cricketers

• Lumbar vertebrae injuries take much time to heal and may not cure well

• Can be causes for spondylolisthesis – forward slippage of vertebrae

• May lead to:

– Disc problems

– Nerve root compression

– Early degeneration of lumbar spine

• Necessary to discover the causes, appropriate treatment, and prevention (Morton S, et al, 2013)

Main causes of LBP in cricket fast bowlers

• Technique

• Physical characteristic

• Bowling workload

Causes of back pain in fast bowlers.

Technique

• Bowling fast with a comparatively less injury risk is considered as an ideal fast bowling technique. (Bartlett RM et al, 1996•Technique –front-on

side-on mixed (combination of front-on and side-on)

The side –on technique is identified as the optimal way to bowl(Annear PT et al, 1992)

The mixed-on technique considered as lead to higher incidence of back injuries(Annear PT et al, 1992)

Extreme lumbar spine extension and rotation happen before ball release in mixed action, thus it lead to raised spinal counter rotation over the delivery stride

Physical characteristic – Flat feet,

strength (Foster et al.1998)

• Low arch/flat feet contributes to stress fracture

• Foot arches act as shock absorbers

• Bowlers with less of an arch may be more prone to get stress fractures because they experience high vertical ground reaction force (Up to 9BW)

Bowling work load

• Overuse contributes to back pain among cricket bowlers. (Stretch RA. 2013)

• Repetitive micro trauma is the cause of overuse injuries. (Elliott B. 1996)

• It is possible to get an injury when applying small forces for a long time even when it is lower than the critical limit of the particular tissue

Influence of ground reaction forces

(GRF) on lower back pain

GRF

”The reaction force supplied by the ground is specifically called the ground reaction force” (GRF)

You need a title for this one.

High peak ground reaction forces areconsidered to be one of the main causes oflower back injuries in fast bowlers (Bartlett,S to ck i l l , E l l io t , & Bu rne t t , 1996 ) .

The similar result observed in other similar sports as well. Ex 32 % of percent of javelin throwers sustained back injury, identified as because of high impact vertical forces (Hurrion et al. 1998)

Though, it is not clear about thecorrelation between high impact forcesa n d i n j u r y ( D e r r i c k , 2 0 0 4 ) .

How does GRF contribute to lower back

pain in fast bowlers?

• 3.8-9.0BW and 1.4-4.5BW respectively vertical and peak braking forces reported during the front foot contact phase in studies (Hurrion, Dyson, & Hale, 2000).

• High peak forces coincide with the period of the action when lower trunk movements known to produce high contralateral facet joint contact forces occur (lower trunk extension in conjunction with contralateral side-flexion and ipsilateral rotation (Burnett et al., 2008)

How does GRF contribute to lower back

pain in fast bowlers?

Bowlers experience the highestlumbar loads between frontfoot contact and ball release(Ferdinands, Kersting, &M a r s h a l l , 2 0 0 9 )

Higher ground reaction forceswere observed in bowlers whoproduce a higher bowl releasespeed (Portus et al., 2004)

Factors that modify the GRF

• GRF correlated with a quicker run-up speed, bowling technique, and physical characteristic (Hurrion et al., 2000).

• The motion of the front leg during the front foot contact phase has been implicated as a mechanistic factor in the development of lower back injury in fast bowlers (Foster, John, Elliot, Ackland, & Fitch, 1989; Mason, Weissensteiner, & Spence, 1989

• Bowlers experienced higher ground reaction force with a more extended front knee than flexed front knee at the front foot contact of delivery stride (Elliott, 2000).

• Front knee flexion during the front foot contact phase contribute to dissipate the GRF, thus reduce the occurrence of injury (Foster et al., 1989).

Analysis of relevant studies

• Crewe.H, et al.2013• 40 male fast bowlers (mean age 16.2 years, height 182

cm, mass 70.8 kg• A12-camera VICON MX motion analysis system (Vicon,

Oxford Metrics, Oxford, UK) operating at 250 Hz and a 1.2 m × 1.2 m force plate (Advanced Mechanical Technology Inc., Watertown, MA, sampling at 2000 Hz

• A strong correlation between ball release speed and mean time to peak vertical force (r = –0.311, CI: –0.633 to 0.093, P < 0.05).

• Researchers observed respectively low peak vertical and horizontal forces (4.9BW, 3.OBW) compared to other observed( 9 BW&4.5VBW)

• However, King, M et al, 2016 contradict with above findings as they don’t find any correlation between release speed and vertical ground reaction force

Analysis of relevant studies

(P. Worthington et al, 2012)

A typical ground reaction force trace during the front

foot contact phase(P. Worthington et al, 2012)

Analysis of relevant studies

• P. Worthington et al, 2012.

• 20 elite male fast bowlers(mean ±standard deviation: age 20.1 ±2.6 years; height 1.88± 0.08 m; body mass 81.5 ±7.1 kg)

• 18 camera (M2 MCam) Vicon Motion Analysis System (OMG Plc, Oxford, UK) operating at 300 Hz.GR Force -Kistler force plate (900 x 600 mm, 1008 Hz)

• Vertical peak force (vertical 6.7 ±1.4 body weights)

• Horizontal (braking) 4.5 ±0.8 body weights)• peak forces associated with the planter angle and

heal strike technique

• Increased plantar angle and heel strike technique help to reduce the peak vertical forces.

Analysis of relevant studies

The resultant ground reaction force vector during the initial part of the front foot contact phase for (a) a bowler with a small plant angle and (b) a bowler with a large plant angle. In both graphics the plant angle (darker shading) and trunk alignment angle (lighter shading)are shown.(P. Worthington et al, 2012)

Analysis of relevant studies

• Back injuries to fast bowlers in cricket: a prospective studyFoster.D et al, 1989 #

• 82- high performance young male fast bowlers (mean age 16.8 years)

• Force data were recorded from the Type 9281 Kistler force platform on a Schlumberger Instrumentation

• vertical GRF 5.43 BW

• Horizontal GRF2.45 BW

No significant relationship was determined between the peak vertical or horizontal ground reaction force (GRF) at FFI and back injuries.

While higher forces at FFI were not significantly related to back injuries, the level of the GRFs may certainly predispose a bowler to back injuries if he is required to bowl for a long spell.

Analysis of relevant studies

M.A.King et al 2016

• Does maximizing ball speed in cricket fast bowling necessitate higher ground reaction forces? M.A.king et al 2016?

• 20 elite male fast bowlers• A moderate non-significant correlation was found between

ball speed and peak vertical ground reaction force with faster bowlers tending to have lower peak vertical ground reaction force (r = −0.364, P = 0.114).

• These findings suggest that there does not necessarily need to be a trade-off between maximum ball release speed and the forces exerted on fast bowlers.

• Motion analysis of the lumbar spine in vivo is difficult due to the inaccessibility of the spine; therefore, studies that examine lumbar kinematics during fast bowling are limited.

Future research

• Whether increased lumbar loads are associated with increased lumbar injury incidence ?

• Whether lumbar loads can be reduced through technique modification without compromising ball release speed

• Conduct player specific studies to find out the issues based on each player’s physical characteristics and technique

Conclusion

• There is inconsistent evidenceregarding the contribution ofGRF in back pain. It is alwaysadvisable to use the techniqueswhich will not raise the GRF.

• Increased plantar angle andheel strike technique help toreduce the peak vertical forces

• Front knee flexion during thefront foot contact phasecontribute to dissipate theGRF, and thus reduce theoccurrence of injury

The End