| Here Mel Siff gives us some insight into some of | | | | were performed after a 20-min periodof standing |
| ingenius work back in South Africa regarding | | | | (pre-exercise), 2-min after exercise (post-exercise) |
| Plyometrics (or powermetrics as he liked to call them) | | | | and after a |
| - this is from the group that he formed in 2000 which | | | | 20-min standing recovery (recovery). Back pain and |
| is still going strong - health.groups.yahoo.com/group | | | | muscle soreness wereassessed using an |
| Supertraining/ | | | | analogue-visual scale, at each of the above times and |
| Drop jumps and various standing drills are so widely | | | | also |
| used as a means ofplyometric training that we often | | | | 24 hours and 36 hours after the test. Peak torque |
| seem to forget that they classically may bedone in | | | | during isokinetic kneeextension at 1.04 rad per sec |
| many other ways, such as using the common | | | | was measured immediately before and after |
| children’s swing that weall used to play upon in | | | | theexercise bouts, to assess the degree of muscular |
| public parks. With the latter, you simply arrange | | | | fatigue. |
| aswing near a wall so that you can swing to different | | | | Ground/wall reaction force data were recorded using |
| heights and strike thewall with your feet to provide | | | | a Kistler force platformmounted in the floor for |
| the rebound. For those who have ourtextbook, | | | | drop-jumps and vertically on the rebound wall |
| “Supertraining” (Siff & Verkhoshansky 1999), | | | | forpendulum exercises. Drop-jumps resulted in the |
| see p275 for diagramsof this exercise. | | | | greatest change in stature |
| In this way you do not have to buy a big supply of | | | | (-2.71 mm), compared to pendulum exercises (-1.77 |
| costly “plyo” boxes - allthat you need is | | | | mm) and standing (-0.39mm). |
| some rope, wood and something to hang your swing | | | | Both exercise regimens resulted in a significant |
| from andyou have a very controllable plyometric | | | | decrease in stature whencompared to the standing |
| training device. With a littleingenuity, you can even | | | | condition. Drop-jumps resulted in significantlygreater |
| arrange a wooden wall at hand height that will | | | | peak impact forces (p < 0.05) than pendulum |
| allowyou to shove off with the hands, as well. | | | | exercises (drop-jumps = |
| (”Supertraining” p275 fordiagrams.) | | | | 3.2 x body weight, pendulum = 2.6 x body weight). |
| Of course, you can make these devices more | | | | The two exercise conditions both invoked a small |
| sophisticated and technical sothat you can carry out | | | | degree of muscle sorenessbut there were no |
| accurate biomechanical measurements with them. | | | | significant differences between either. Both |
| Forthose who have our textbook, | | | | exerciseregimens resulted in a non-significant |
| “Supertraining”, page 219, you will see | | | | decrease in peak torque, indicating asimilar degree of |
| adiagram of a special plyometric bench that my | | | | muscular fatigue. Based on the lower in height and |
| senior engineering studentsconstructed at the | | | | lowerpeak forces, it can be concluded that pendulum |
| University of the Witwatersrand (South Africa) in | | | | exercises pose a lower injurypotential to the lower |
| 1992. | | | | back than drop-jumps performed from a height of 28 |
| The same students also constructed various upper | | | | cm. |
| and lower body swings withbuilt in load cells or force | | | | What does this mean for the coach? Well, first of all, |
| plates to measure the forces exerted duringimpact. | | | | it stresses thatthere is a very real place for use of |
| Quite recently I came across the following research | | | | the PLYOMETRIC SWING as a safe andeffective |
| article that carried outmuch the same sort of work | | | | form of explosive training. Secondly, it shows that |
| that my engineers had been doing. I think thatmany | | | | the |
| of you will find the results interesting. | | | | *potential* for injury is greater with drop jumps, |
| Fowler NE, Lees A & Reilly T Changes in stature | | | | because of the greaterimpact forces exerted on the |
| following plyometricdrop-jump and pendulum | | | | whole body. |
| exercises. Ergonomics 1997 Dec; 40(12):1279-86 | | | | However, it needs to be pointed out that the body |
| The aim of this study was to compare the changes | | | | can adapt to such stresses,but this potential for |
| in stature following theperformance of plyometric | | | | injury is a good reason why any drop jumps should |
| exercises using drop-jumps and a pendulum swing. | | | | beprescribed carefully and intelligently, especially |
| Eight male participants aged 21.7 +/- 1.8 years with | | | | among novices whosemusculoskeletal system has not |
| experience of plyometrictraining gave their informed | | | | adequately adapted to the impulsive loading. |
| consent to act as subjects. Participantsundertook | | | | Regarding the experiment, it should also be pointed |
| two exercise regimens and a 15-min standing test in | | | | out that, if 50repetitions are to be done, then it is |
| a random order. | | | | essential that they be done in limitedsets of a few |
| The exercises entailed the performance of 50 | | | | repetitions at a time, not like some sort of |
| drop-jumps from a height of 0.28m or 50 pendulum | | | | enduranceexercise. In the USA many coaches tend |
| rebounds (off a wall). | | | | to prescribe far too many plyometricrepetitions at a |
| Participants were instructed to perform maximal | | | | time. More is not necessarily better. In the case |
| jumps or rebounds using a | | | | ofplyometrics, quality is definitely more important |
| ‘bounce’ style. Measurements of stature | | | | than quantity. |