Dr. Glenn Fleisig and his research group at ASMI revealed a research—as we’ve got at Driveline—investigating the results of weighted balls on pitching mechanics utilizing optical movement seize (the gold-standard in biomechanics measurement).
The ASMI and Driveline research each investigated how pitchers’ mechanics modified as they threw in a different way weighted balls, and each research discovered related modifications. Each research discovered that peak rotational speeds decreased, torso ahead tilt elevated, and pitch velocity decreased as ball weight elevated from 3 ounces to 7 ounces, whereas the ASMI research produced just a few extra outcomes (though they didn’t regulate for a number of comparisons). One vital drawback with these research, nevertheless, is that they in contrast mechanics by measuring just a few handfuls of single values for every throw, slightly than evaluating measurements all through the entire throw.
These singular values to explain the biomechanics of a throw are calculated by taking varied measurements at commonplace cut-off dates. For instance, measuring pelvis place on the time when the pitcher’s entrance foot strikes the bottom (foot plant, FP) or when the ball is launched from the hand (ball launch, BR). We are able to additionally take measurements once they attain their international maximums or minimums, comparable to most elbow flexion, all through the throw. Nonetheless, there may be way more to the pitching supply than just a few instantaneous positions, so having the ability to examine metrics for the complete period of the throw is invaluable. To deal with this limitation, we used statistical parametric mapping to match the complete throw utilizing the identical dataset as our pre-printed study. Right here is an instance with ahead trunk tilt: Would you slightly examine trunk tilt all through two entire throws just like the plot right here on the left, or examine the diploma of trunk tilt in these throws at one time level, as seen within the plot on the suitable?
We talk about this limitation in additional element in our first full signal analysis post with an instance of our resolution, however, in abstract, full sign evaluation utilizing statistical parametric mapping (SPM) permits us to match complete throws from begin to end, slightly than at solely a handful of time factors. We also needs to point out that full sign evaluation has its personal limitations because of a lot of comparisons and since the alerts have to be time normalized, however these are overshadowed by the advantages of full sign evaluation.
Right here’s a fast abstract of the outcomes of the research utilizing full sign evaluation:
- The arm strikes sooner with lighter balls and slower with heavier balls when it comes to elbow extension and shoulder inside rotation.
- Lighter balls are related to a bit extra most elbow flexion than heavier balls are, however not a lot.
- Athletes attain a higher diploma of shoulder inside rotation simply earlier than ball launch with lighter balls, however not by a lot.
- Heavier ball throws are related to extra ahead trunk tilt simply earlier than ball launch (chest extra parallel with the bottom), however not by a lot.
- Athletes start to withstand exterior rotation earlier when throwing heavy balls than when throwing gentle balls, however not by a lot.
All issues thought-about, the one main impact of three – 7 ouncesweighted baseballs is the pace at which athletes deploy their arms. Throwing these balls resulted in little to no ‘virtually vital’ variations in pitching mechanics. This helps utilizing weighted balls to probably prepare extra effectively, enhance athlete consolation, and prepare for energy and pace.
And now for the specifics.
For this investigation we use the identical statistics package deal as within the aforementioned evaluation (statistical parametric mapping) to match mechanics from the beginning of the throw to the end. For instance, one of many metrics we investigated was elbow flexion/extension velocity. The impact of ball weight on elbow flexion was evaluated for the entire throw utilizing an ANOVA statistical check, and because the check confirmed that ball weight affected elbow flexion, we in contrast elbow flexion between pitches with completely different weights (3 ouncesvs. 4 oz, 4 ouncesvs. 6 oz, and many others.).
Statistical distinction between circumstances is proven by the purple line on the suitable plot; when it exceeds the edge of significance (black horizontal dashed line on the suitable hand aspect), we will say with confidence that the 2 circumstances are statistically completely different. For instance, the purple line exceeds the horizontal dashed line close to the tip of the plot beneath, telling us that ball weight considerably affected this metric close to the tip of the throw, since we all know that the ball is launched at body 300 on the x-axis.
This course of is mainly repeated for all chosen metrics to see not solely what elements of the throw are completely different when throwing completely different ball weights however when within the throw they’re completely different.
For the metrics which are proven to be considerably affected by ball weight, we examine every ball weight to see which are literally completely different. You’ll be able to see the outcomes of this sort of comparability beneath, which compares throws with the three ouncesweighted baseball to throws with the 7 ouncesweighted baseball.
Just like our investigation utilizing focal point information (e.g. evaluating pelvis angle at entrance foot plant between 3 ouncesand 4 ouncesthrows), we grouped biomechanical metrics into classes to explain total forms of actions within the throw. These classes had been arm place measurements comparable to elbow flexion, mid-section place measurements comparable to pelvis rotation angle, lead knee flexion, the one decrease physique measurement we took, kinematic velocity measurements comparable to torso rotation velocity, and kinetics comparable to elbow valgus torque. The metrics that had been considerably affected by ball weight inside topics (which principally coincided with our focal point evaluation) included:
- Arm Kinematics
- Elbow Flexion/Extension
- Shoulder Rotation
- Mid-Part Kinematics
- Anterior/Posterior Trunk Tilt
- Kinematic Velocities
- Elbow Flexion/Extension Velocity
- Shoulder Rotational Velocity
- Arm Joint Kinetics
- Elbow Valgus Torque
- Shoulder Rotation Torque
Which means that inside every topic (every participant within the research in comparison with himself), the above metrics had a minimum of one cut-off date all through the throw which differed when throwing completely different ball weights.
Now let’s look additional at every of these kinematic and kinetic modifications.
Elbow flexion and shoulder rotation had been each considerably affected by ball weight within the arm kinematics class. The 2 different metrics examined within the arm kinematics class, shoulder horizontal abduction and shoulder abduction, didn’t present a major impact from weighted balls.
We’ll begin with elbow flexion:
The purple, vertical strains within the plots above signify the second of foot plant. You’ll be able to see that the black line on the suitable plot reaches statistical significance (by crossing the horizontal dashed line) only a bit after foot plant that means that the 2 circumstances turn out to be completely different at this level within the throw. In case you take a look at the identical spot on the left graph, you possibly can see that the distinction is across the peak of the elbow flexion sign with the three ouncesline being increased than the 6 ouncesline, that means 3 ouncesthrows resulted in a considerably increased peak elbow flexion on common. Larger peak elbow flexion corresponds to the arm being extra bent on the elbow—their hand being nearer to their physique. That is what we present in our focal point evaluation as effectively.
Now for shoulder rotation:
This 4 ouncesvs. 7 ouncescomparison exhibits how shoulder rotation is affected by weighted balls, however it’s not the place you would possibly suppose. Most shoulder exterior rotation will not be affected by weighted baseballs (a minimum of 3 oz – 7oz) in a max intent pitch, however lighter balls have extra inside rotation on the finish of the throw, proper earlier than ball launch.
This is smart for just a few causes. First, shoulder inside rotation velocity is quicker with gentle balls so it is smart that gentle balls would have extra inside rotation later within the throw. Second, the lighter ball weights might require a decrease trajectory out of the hand, which might have an effect on shoulder positioning at ball launch. Final however not least, the place of the torso at ball launch is barely completely different, which is able to have an effect on shoulder rotation since shoulder angles are calculated because the place of the humerus (higher arm) with respect to the place of the torso. Extra beneath.
To check mid-section mechanics, we included comparisons of pelvis and trunk (torso) ahead and lateral tilt, pelvis and torso rotation, and hip shoulder separation. Solely trunk ahead tilt was considerably affected by weighted balls, as we see right here.
On the finish of the throw, athletes exhibited considerably extra ahead trunk tilt (chest extra parallel with the bottom) with heavier balls simply earlier than ball launch, which we additionally present in our focal point evaluation. That is attention-grabbing in its personal proper as a result of it means that athletes extra actively use their mid-sections to throw heavier balls, however it’s additionally attention-grabbing as a result of it ties in to shoulder rotation. Since shoulder angles are calculated by evaluating the place of the humerus (higher arm) relative to the torso (the chest), if the torso is tilted additional ahead when throwing heavier balls however the arm is at an identical place at ball launch, shoulder exterior rotation goes to be higher.
Shoulder inside rotation velocity and elbow extension velocity had been each affected by weighted balls, however pelvis and trunk rotational velocity and entrance knee extension velocity had been unaffected.
Gentle balls measured when it comes to each elbow extension velocity and shoulder inside rotation velocity elicited increased peaks, that means athletes prolonged their elbow sooner and internally rotated their shoulder sooner when throwing lighter balls. That is considerably intuitive and in addition what we discovered with our focal point evaluation.
The one two kinetics examined on this evaluation had been the elbow varus second (may be considered the identical factor as valgus torque) and shoulder inside rotation second (the torque concerned within the inside rotation motion of the shoulder). In our focal point evaluation, we didn’t discover a vital distinction in peak values of both of those metrics, however we wished to have a look at extra than simply the height values on this case. The outcomes are as follows:
We discovered (once more) that peak values in each metrics of stress/kinetics/torques (whichever you favor to name it) weren’t affected by weighted balls on common. We did discover a vital distinction between gentle and heavy balls at foot plant, however this distinction will not be virtually necessary as a result of it occurs when the torques are proper round zero. You’ll be able to see that the three ouncesthrows in each elbow varus second and shoulder inside rotation second produce considerably decrease values than the 6 ouncesat foot plant, however it’s a distinction of seven.16 Nm for 3 ouncesand 13.04 Nm for six oz.
Since each of those values are so low in comparison with their respective peaks (about 147 Nm for each), the impact we see right here of weighted ball on shoulder and elbow torques will not be an implication for damage; slightly, this impact has extra implications on timing evaluation, i.e. suggesting that athletes begin to withstand exterior rotation a short while earlier with heavy balls than with gentle balls.
After analyzing generally used discrete factors of curiosity all through the throw, incorporating beforehand revealed literature, and in addition doing full sign kinematic evaluation on our present dataset, there may be one factor we’ve got discovered about 3 – 7 ouncesleather weighted baseballs: they don’t change pitching mechanics hardly in any respect. Athletes transfer their arms sooner with lighter balls and slower with heavier balls, however so far as positioning and motion results, they’re fairly minimal.
Positive, once you add a motion constraint into the combo like we do right here at Driveline, the mixture of a weighted implement and the constraint might have an effect on how an athlete strikes. Nonetheless, that may be a query for an additional day. What we now find out about conservatively weighted overload and underload baseballs is that they have an effect on how briskly an athlete’s arm can transfer, they have an effect on some finish ranges of movement of arm and mid-section kinematics (not those you’d suppose), they usually have little to no affect on elbow and shoulder kinematics.
Weighted baseballs do impact throwing kinematics; nevertheless, it’s necessary to notice that the magnitude of this impact may be very small and sure virtually insignificant. For instance, as we noticed with the focal point evaluation, the best imply distinction in elbow flexion between any two ball weights was a 2 diploma distinction between 4 ouncesand 6 ouncesthrows. The standard vary of movement of elbow flexion/extension was round 90 levels. Which means that the largest impact between completely different ball weights was a few 2% distinction. Doesn’t appear virtually vital, does it?
Since 3 – 7 ouncesweighted baseballs don’t change mechanics very a lot, let’s speak about how they are often beneficial. There are some things I believe needs to be thought-about: energy/pace adaptation; throwing health and throwing quantity; coaching effectivity; and athlete consolation.
Many coaching packages (outdoors of baseball as effectively) use underload and overspeed coaching. The speculation is that utilizing underload implements or aiding actions to allow them to be carried out sooner would require the physique to recruit completely different motor items and study to make use of sooner management patterns. If that is so, then utilizing 3 and 4 ouncesweighted baseballs can be a low-risk addition to a coaching program, since we noticed that the athletes’ arms moved sooner when throwing a lighter ball with comparatively no antagonistic results on throwing mechanics or stress on the physique/arm.
Constructing throwing health and rising quantity in a coaching program may be executed by various throw frequency, throw depth, complete variety of throws, and altering the load. Small will increase in ball weight can add extra load to a throwing train with out regressing mechanics, so throwing these leather-based weighted baseballs could be a good method to altering complete workload (for lack of a extra encompassing time period) with out additional rising complete variety of throws.
Equally, since mechanics don’t change with a 7 ouncesbaseball (2 ouncesoverload), possibly it’s attainable to get related coaching results with fewer throws by utilizing the heavier ball. After I head into the burden room and arrange the bench press for just a few units, I can attain max exertion with fewer reps if I exploit a heavier load. So, if I’ve much less time to do a exercise or a warm-up, possibly I’d load up the bar a bit greater than my typical load if I knew it wasn’t going to adversely have an effect on my motion.
A motion like a throw through which each throw locations the arm underneath a excessive diploma of stress is extra complicated than the bench press, which helps the usage of a light-weight overload even additional. If I can place my arm underneath much less excessive stress repetitions and get a extra environment friendly coaching impact by utilizing a light-weight overload baseball, that appears like a good suggestion.
A coaching research (or a number of coaching research) can be required to make certain of those results, however figuring out that mechanics don’t change considerably when throwing 3 – 7 ouncesweighted baseballs makes this a much less dangerous concept to pursue.
If an athlete actually enjoys utilizing overload or underload baseballs to reinforce how their physique and arm really feel for competitors or coaching, we will now say with confidence that their mechanics shouldn’t change consequently (a minimum of not acutely, intra-session). Figuring out this, if an athlete enjoys utilizing these completely different ball weights, a coach or coach needs to be snug with their use.
We now have not noticed any vital antagonistic results of utilizing 3 – 7 ouncesleather weighted baseballs for throwing. That is primarily based on two peer-reviewed, managed research of pitching mechanics.
In case you, an athlete in your coaching program or group, a teammate, or anyone else is snug utilizing leather-based weighted baseballs for pitching, there isn’t any purpose to not (in the event that they’re used responsibly). With correct heat up (i.e. don’t throw a 7 ounceswith max intent proper once you arrive on the area), correct on-ramping (begin with conservative quantity and improve from there), and correct monitoring (if the overload/underload throws appear to be related to uncommon soreness or ache, regulate quantity/depth appropriately), there isn’t any compelling purpose to not incorporate these implements.