TRANSMISSION OF FORCE THROUGH THE , , AND THUMBLESS BOXING AS A FUNCTION OF VELOCITY

Paul K. SMITH

Department of Physical Education West Chester University .-, est Chester PA 19383

Two studies were designed, using Smith and Hamill's (1985) protocol, to compare the foam Karate Glove, the conventional Boxing Glove, and the '!'hlllltlless Glove on selected i~ct ch~racteris~i?s of peak force, tin~ to peak force, average force and impulse at dIfferentIal velocItIes and with repeated impacts.

~CD: sroDY 1 sroDY 1 was to determine the effect on selected kinetic parameters of inpact with the Karate Glove, the Boxing Glove, and the Thlllltlless Glove at specific velocities using a mechanical impactor to eliminate mass variations due to human physical interactions. A 3 * 5 design with Multivariate Analysis of Variance and Duncan's Range Test followup procedure was used to analyse the data. Gloves were fitted over a Red oak fist with an 8.98 sq cm surface area which was mounted on a specially built impact device.

ure I. Karate, boxing, and thumbless glove.

49 Figure 2. J\ppar;ltus layout for <;t ,IIJy I.

RESULTS AND DISCUSSION: SlUDY 1 Significant effects were found for Glove Type, velocity, and the Glove Type-Velocity interaction.

TABLE I NEANS AND STl\NDl\RD DEVIATIONS OF KINETIC PlIRAMETERS BY GlJJIlE TYPE

variable Karate Glove Boxing Glove ThurIDless Glove I-ratio

b a b Peak Force X 1212.977 1530.499 llSO.7l1 22.35 • (N) SO 962.823 1345.079 1020.128

b a a Time to X 0.01.6 0.019 0.018 8.38• Peak Force (s) 50 0.003 0.006 0.004

a a b Average Force X 426.900 ,b 440.296 385.893 3.67 • (N) 50 242.379 340.493 247.455

a b Irrpulse X 25.251 23.984 23.81ab 20.59• (N-s) SD 9.741 8.585 8.652

• Means with the same superscripts are not significantly different (2, < .05). 50 The Boxing Glove had hig er peak force, longer time to peak force, and lower impulse scores than the Karate Glove. There was no difference between the Boxing Glove and Karate Glove with respect to average force. Peak and average forces were not different at the lower two velocities but were different thereafter. Time to peak force differences were present between the 1.0 to 1.5 rn/s level and between the 2.0 and 2.5 rn/s velocities. Impulse displayed significant differences among all velocity levels. It should be stressed that the higher impact levels from this study were equivalent to the lower momentum estimates from the studies, which was erX)ut 40 N-s. Values from this study must therefore be considered conservative in terms of actual forces that could be applied by higher skill -level punchers. TAIlLE II HEI\NS AND Sl'I'.NDARDS OF KINETIC PI\RAI-IETERS BY VELCCITY

Variable 0.5 m/s 1.0 m/s 1. 5 m/s 2.0 m/s 2.5 m/s f.-ratio

a a b c d Peak Force X 355.221 391. 786 926.353 1651.137 3215.810 506.84 * (1'1) 50 28.945 54.274 179.626 292.586 520.990

a a b c d Time lo X 0.021 0.021 0.016 0.015 0.012 105.20* Peak Force (s) 50 0.002 0.004 0.001 0.001 0.001

a a c d Average X 156.047 178.881 341.650b 550.500 861.404 237.13 * Force (1'1) 50 18.826 33.43 32.790 34.787 151.891

a b c d e IflllU15e X 14.786 16.034 23.061 30.08l 37.792 1890.54 * (1'1-5) 50 0.254 1.203 0.982 1.260 1.333

* Means with the same superscripts are not significantly different (I? < .05). The significant interaction effects were noted as the peak force curves diverge with the increase of velocity (Figure 3.). After the 1.5 rn/s velocity the Boxing Glove had increasingly larger peak force values than the Karate Glove and Thumbless Glove. At higher velocities the Karate and Thumbless Gloves spread the forces over a longer time period. Average force would tend to be higher for short contact time durations and impulse would tend to be higher for longer contact times. While the Boxing Glove transfers less momentum, it transmitted higher peak forces. This finding indicates the Boxing Glove to be more likely to damage hard tissues where less contact time is needed, but the Karate Gloves would tend to cause a greater acceleration of an object at the tested impact levels. It is important to keep in mind that only relatively low impact forces were used in this study.

MEl'HOO: STUDY 2 STUDY 2 was to determine the general trends of the kinetic parameters across 50 trials using virgin gloves. The apparatus use in the previous study was used in this analysis. Fifty impact trials were administered to each glove type at 2.0 rn/s velocity and data were recorded the first and every fifth trial thereafter such that 11 trials were analysed. Fifty impacts is the awroximate nllll'ber of blows in one round of boxing. Trend analysis for linear, quadratic, and cubic effects were used to detect the best fit across the 50 impact trails. 51 T 0.0258­ ~S03-1 I t1 E a.BZZ5 T ('", 0 "\ LJ ,, l p a.82G9 '1, ...... E "'...... A ...... "­ / ;J K ...... '/, ...... a.BI75 ...... "t, ...... " F ...... , LJ ...... ;// 0 "­, (J1 I ~ R "­ '" H //fl C 8.al l...... // E 1I "­ // ~ E le p//// I ~ U /~;::1/ H 0.B125 T 0 S ~--~ . H E S C G.al Ir-

u 8.5 I.B 1.5 2.B 2.5 8.B 0.5 I.B 1.5 2.8 2.5

VELOClTY (I\!SEC) V!lOCITY WSEC)

LEGHIJ: SLOVE fHHl BOWlS -Ir--H KARATE ~ MiLESS LEGEl'(): GLOYE fHHl BOXING -Ir--Ir-iJ KARATE ...... Tlt1LESS

figure): Peak [orce as a function of veloc.ity for k;tr:tte. FJgufn l,: Ti~ to (ll!:nk Corce flS " (unction DC veloci.ty for box lng I and thllmbless gloves. kit ra t~ I b(l:dn~, and thumblcss Bloves. IOcg A 4 V E R I A ;:4 11 35 G P / U E /,'l' / L / F // S 3 / 0 / E /, R I / .'/ C / tf,'/ E tI 25

I H VI w H E U 2B H T E 0 Y 200 H ~;;;r' T - 15 r,:::=-­ 0 S H E S C B I I""" , I " , " "I' B.O B.5 I.B 1.5 2.B 2.5 B.B B.S I.B 1.5 2.B 2.5

VELOmy (tvSEC) VELOCITY (tvSEC)

LEGO~: GlOVE lH3-!3 BOXING 'ir-Ir-fJ KARATE H4 mlLEss LEG[}l): GLOVE il--IHl BOXIN G irlr-IJ KARA IT +--Ht T1-lJILESS

figure 5: Ave-rage force 1'8 0. function of velocity for karate, 'i~ure 6: rl'hplll:;c (1$ a funr"tilJn of v~loclty for kar;ttc. hoxing, and thumbless gloveH.. boxing, nnd lhumblerus J:.lovcs. FESULTS AND DISCUSSION: STUDY 2 Peak force, time to peak force, average force, and inpulse variances were accounted for better with the linear function than quadratic or cubic functions. An exception was the impulse variable for the Boxing Glove in which no significant trend was found. The presence of higher order trends indicated a complex phenomena took place. However, since only one glove of each type was tested, results will be reviewed from a more practical than statistical perspective.

For peak force the R2 was .81 for the Thumbless Glove, .78 for the Karate Glove, and .70 for the Boxing Glove. The slope for the Boxing Glove was 3 times that of the Karate Glove, which in turn was about 3 times that of the Thumbless Glove (108, 36, and 13, respectively). A sharp rise from the 1st to the 5th trial probably indicated the initial collapsing and air escapment from the materials. With the Boxing Glove this effect 1/.as greater as forces rose lTt.Ich quicker for that nl.llJber of irrpacts. All glove types had leveled at the 15th irrpact, but by the 50th trial the Boxing Glove had risen 96%, from 1,484 to 2,9l3~. The consistency of the Ensolite was evidenced by the Karate Glove rising only 27%, from 1,626 to 2,078 N. The hair-foam composition of the Thumbless Glove was even nore consistent rising only 12%, from 1,069 to 1,196 ~. For average force R2 values were .81 for the P~xing Glove, .73 for the Thumbless Glove, and .68 for the Karate Glove. The slopes were 39.16, 5.73, and 5.15 respectively for the Bo.xing, Karate, ond Thumbless Gloves. While the Boxing Glove started at just over half the average force transmitted by the Karate glove, it had surpassed the fOaI;l glove by the 20th trial. The Thumbless Glove values r611ained consistent at a level of about 450 N. By the 50th trial the Boxing Glove average force had risen 118%, from 370.20 to 806.33 ~, while the Karate Glove values rose only 12%, from 579.79 to 649.40 N. The ThurnbJess Glove average force increased 14%, from 422.11 to 479.45 N. Impulse slopes for all glove types were practically horizontal 0.03, 0.09, and 0.11, respectively, for the Boxing, Karate, and Thumbless Gloves. Thumbless Glove irrpulse rose 4%, from 27.88 to a rreximum of 28.98 N-s. The Karate Glove values only rOse 4%, from 31.22 to 32.22 N-s and the Boxing Glove values only 2%, from 28.88 to 29.58 N-s. With impact forces from this test, the Boxing Glove would attenuate forces below the concussion level only on the first few irrpacts. After the first 5 blows, impacts using either the Karate or Boxing Gloves would be within the zone of concussion, which is about 588 N with a 26 ms contact time for a unit mass. However, the Boxing Glove would be further inside the zone. The Thumbless Glove would be just barely below the concussion cutoff level. Again, it should be ren:el1lbered that these are very conservative applied loads in relation to those of capable punchers. Mechanical impact velocities in these studies ranged from about H to 21 percent of the velocities generated by human punchers. The 4.71 kg mass of the irrpactor corresponds to both the striking masses used in previous studies and the n~ss of the human head (smith and Hamill, 1985). None of the glove types tested could be considered "safe" in terms of protection from concussion, though the Thumbless Glove appears to offer more of a safety factor than the others and should be employed for both partner training and competition. The Boxing Glove is more likely to pernlit hard tissue damage by virtue of its higher forces transmitted and the Karate Glove would more likely permit concussions as determined from th~ higher impulse levels, whereas the Thumbless Glove seems to combine the advantages of f (. C~ unl -;rrpulse attenuation at the inpact levels tested.

54 16,U03 29 /10 300" Human olerancc of concussion. Developed at \~ayne State Univer'ity by HoLi'son and TholJ,"s (Courtesy of V R. l'I,!J:lG :tif}t! 200 Jlodgson)

,IIG!J 25'lIl 260 ~ 1\ ju~tcd for 5.41 kr,- l1las~ u f1 1::,802 , 2:152 -;;0 210 ~ c .. , ,3("", 215 220· "0 c c IO,G6 Igc.u .'1 200 ~ u., u 9,001 ... liG I "... 180 ..." ~ ., ... 1~6B ,5 5 "u u" 160 " " • ~rjl .. ... ~ 3 2 ., UO " " " G -101 5 11 i6 ...,..'i 120­ ;:, , .., r • :~., 1 c, 9RO " 100 :tbou 34 Ps ~; :: CJ ," ,. / :: ,1. :!G': .;" 'ill I ..," 80 ------­ z r cone ssion :),~OO 588 GO· i~__ ,about 90 N's -­------: ­ - -­- ­- --­ -. - ­- -- ­ ~:------2, 1~I~. J!l2 D I ' ] ., ll;"~ 1~6

o Zon~ of no concussion '----~--'--,---,---,---r-_t___,,__,__,- o 10 IS 20 15 JO 35 .1() 15 Du,""tion of impact (msec)

PEFEREU:ES

Birrer, R. R. & Birrer, C. D. (1982, June). injuries. Physician and Sportsmedicine. 10(6), 103-104.

Dessureault, J. & Therrien, R. G. (1981). Energy absorption and force transmission characteristics of boxing gloves. In Regie de la securite dans les sports. in Q,.Jebec: a study. Q,.Jebec: Government of Q,.Jebec.

Hassell, R. G. (1982). Conversations with the master: ~~satoshi Nakay~a. St. Louis: Focus Publications.

Hodgson, V. R. &- Thomas, L. M. (1981, NovE!llDer 13). Boxing gloves conpared using c1ll11UllY head acceleration response. (Report to the New York State Athletic Commissioner) •

~re, M. (1983, January). A pall over boxing. Physician and sportsmedicine, 11(1), 21. Schmidt, R. J. (1975, Spring). Fatal anterior chest trauma in karate training. Medicine and Science in Sport, 1, 59-61. Smith, P. K. & Ramill, J. (1985). Karate and boxing glove impact characteristics as functions of velocity and repeated irrpact. In J. Terauds and J. N. Barham (Eds.) Biomechanics in Sports II. Del Mar, CA: Academic Publishers.

55