Exercise Ups Your Antibacterial Defenses, Kettlebells Boost VO2, Medicine Balls Boost Throwing Velocity, Footwear Has Little Effect on Jumping Performance - Research Quickie

If you are a handball player or someone else who "throws", you can consider medicine ball training an effective means to increase your throwing velocity.

Since the last edition of the short news focusing solely on exercise science was a huge success, I will devote today's SuppVersity article to the same topic: The latest from the realms, ah... I mean laboratories of strength and conditioning researchers.

In that, we will be dealing with the "immune" response to exercise. I will take another look at the VO2 boosting prowess of kettlebell training (done right). I will examine the outcome of a study investigating the effects of being barefoot, minimally shod or shod on jumping performance and muscle activation. And I will close the exercise research update with a study investigating the effects of medicine ball training on handball players' throwing performance.

• Working out increases amount of antimicropial proteins in the mouth (Gillum. 2015) - The scientists speculated that sleep deprivation and exercise, both of which have been shown to have a negative impact on the strength of the immune system would have similar effects on the salivary antimicrobial proteins (AMPs).
  
  To test this hypothesis Gillum et al. measured the amount of these AMPs in response to sleep loss before and after exercise. 4 males and 4 females, (age: 22.8+/-2; VO2pk: 49.1+/-7.1 mL/kg/min) completed 2 exercise trials consisting of 45 min of running at 75% VO2pk after a normal night of sleep (CON) and after a night without sleep (WS). Exercise trials were separated by 10+/-3 days. Saliva was collected before, immediately after, and 1 hr after exercise. LL-37, HNP1-3, Lactoferrin (Lac) and Lysozyme (Lys) were measured.
  

  Figure 1: Exercise ramps up the "AMP"-part of the immune defenses acutely (Gillum. 2015).

  They found that sleep loss did not affect the concentration or secretion rate of AMPs before or in response to exercise. However, exercise increased the concentration from pre to post exercise of LL-37 (pre: 15.5+/-8.7; post: 22.3+/-16.2 ng/mL), HNP1-3 (pre: 2.2+/-2.3; post: 3.3+/-2.5 [micro]g/mL), Lac (pre: 5234+/-4202; post: 12283+/-10995 ng/mL), and Lys (pre: 5831+/-4465; post: 12542+/-10755 ng/mL), p<0.05.
  
  In that, the secretion rates were higher immediately post and 1 hr post exercise compared to pre exercise for LL-37 (pre: 3.1+/-2.1; post: 5.1+/-3.7; +1: 6.9+/-8.4 ng/min), HNP1-3 (pre: 0.38+/-0.38; post: 0.80+/-0.75; +1: 0.84+/-0.67 [micro]g/min), Lac (pre: 1096+/-829; post: 2948+/-2923; +1: 2464+/-3785 ng/min), and Lys (pre: 1534+/-1790; post: 3042+/-2773; +1: 1916+/-1682 ng/min), p<0.05.
  
  As the scientists point out, "[t]hese data suggests that the major constituents of the mucosal immune system are unaffected by acute sleep loss and by exercise following acute sleep loss. Exercise increased the concentration and secretion rate of each AMP suggesting enhanced immunity and control of inflammation, despite limited sleep."
• Another study to confirm: Kettle bells increase VO2max... if they are used correctly (Falatic. 2015) - Falatic et al. have presented similar results in a previous study, discussed / mentioned in my recent article on kettle bell training (read it!), already. In their latest experiment, the researchers examined the effects of a kettlebell training program on aerobic capacity once more - with the same intense 15:15 design, i.e. 15 seconds maxing out, 15s "rest".
  
  

  2015 may offer a chance to spice up your routine with kettlebells | more.

  In this case, their subjects were seventeen female NCAA Division I collegiate soccer players (age 19.7 +/- 1.0 years, height 166.1 +/- 6.4 cm, body mass 64.2 +/- 8.2 kg) who completed a graded exercise test to determine maximal oxygen consumption (VO2max). Participants were placed into a kettlebell intervention (KB) group (n = 9) or a circuit weight training control (CWT) group (n = 8). Participants in the KB group completed a kettlebell snatch test to determine individual snatch repetitions. Both groups trained 3 days a week for 4 weeks in addition to their off-season strength and conditioning program.
  
  The KB group performed the 15:15 MVO2 protocol (20 min of kettlebell snatching with 15 s work and rest intervals). The CWT group performed multiple free weight and dynamic body weight exercises as part of a continuous circuit program for 20 min. The 15:15 MVO2 protocol significantly increased VO2max in the KB group. The average increase was 2.3 ml[middle dot]kg-1[middle dot]min-1, or approximately a 6% gain. There was no significant change in VO2max in the CWT control group.
  
  Thus, the scientists conclude: "[T]he 4-week 15:15 MVO2 kettlebell protocol, using high intensity kettlebell snatches, significantly improved aerobic capacity in female intercollegiate soccer players and could be used as an alternative mode to maintain or improve cardiovascular conditioning" (Falatic. 2015).
• Footwear doesn't effect jump performance, but it does change the muscle activation (Harry. 2105) - Likewise published among the "accepted papers" on the website of the Journal of Strength Conditioning Research is a paper in which the researchers investigated the effects of footwear on kinetics and lower extremity electromyographic (EMG) activity during the vertical jump and standing long jump.
  
  What they found, when they had fifteen men perform the two jumps types in three footwear conditions: barefoot, minimal shoes, and cross-training shoes was that there are no significant differences in jump displacement, peak ground reaction forces (GRF), countermovement and propulsive phase durations, vertical impulse, peak countermovement or average propulsive EMG activity.
  

  Figure 2: Differences in RMS EMG activity of soleus and vastus medialis muscle during standing long jump (SLJ) and vertical jump (VJ) condition (Harry. 2015).

  What did differ, though was the peak propulsive RMS EMG between barefoot and minimal shoes (p = 0.030) and minimal shoes and shod (p = 0.031) conditions for the soleus during the vertical jump, and for average countermovement EMG of the semitendinosus/ semimembranosus during the vertical jump between barefoot and shod (p = 0.039). Furthermore, moderate-to-large effect sizes (> 0.59) were found between conditions for horizontal GRF, propulsive phase duration, average EMG amplitude and duration of EMG activity during the countermovement. Moreover, the
  

  "[p]articipants reported higher comfort ratings when shod compared to barefoot and minimal shoes for both jumps. Participants also perceived better performance when shod compared to barefoot and minimal shoes for the vertical jump only" (Harry. 2015).

  Since there are no acute differences in displacement between barefoot, minimal shoes, and cross-trainer shoes during vertical and horizontal jumps, it will thus depend on (a) whether you like training minimally shod or barefoot and whether (b) the differential muscle activation due to the tested footwear matters for you due to athletic or safety reasons.
• Medicine ball training for handball players (Reader. 2015) - According to the latest study by Christian Reader et al. the use six weeks of medicine ball training (MBT) has significant beneficial effects on some crucial performance parameters of female handball players.
  
  In the corresponding experiment, twenty-eight players (mean +/- SD; age: 20.8 +/- 3.3 years, height: 170.5 +/- 5.6 cm, body mass: 65.2 +/- 8.0 kg) were randomly assigned to a MBT group (TG; n=15) and a control group (CG; n=13). TG performed a supervised MBT program, three times a week for a total of six weeks, focussing on handball-specific movement patterns. Both groups, TG and CG, also conducted a supervised shoulder injury prevention program with elastic tubes, as part of the warm-up, finishing with regular handball throws.
  

  Figure 3: Changes in throwing velocity (significant difference), throwing performance (non significant) and goal success (non significant) in response to medicine ball vs. control training (Reader. 2015).

  The results indicate that there was a significant group x time interaction in throwing velocity (P < 0.001) with the TG post-test results being significantly higher compared to CG (d = 2.1), and also a significant main time effect (P < 0.001), with an increase in throwing velocity of 14% (d = 3.0) and 3.7% (d = 0.3) for both TG and CG, respectively. Throwing precision did not significantly differ between groups and time points. Isokinetic strength measures revealed a significant group x time interaction (P < 0.05) with the TG post-test results being significantly higher compared to CG (d = 0.9) and also a significant main time effect (P < 0.01) with an increase of 15% (d = 0.9) in concentric shoulder internal rotation at 180[degrees]/s in the dominant arm in TG, whereas no significant changes occurred in CG.
  
  As Reader et al. point out their study does therefore "indicate that six weeks of MBT elicit significant improvements in functional performance (i.e., throwing velocity) in female handball players, while throwing precision remained unaffected. MBT exercises seem to be a useful and inexpensive strength training strategy in enhancing functional performance by closely mimicking sport-specific movement activities" (Reader. 2015).

References:

• Falatic, J. Asher; Plato, Peggy A.; Holder, Christopher; Finch, Daryl; Han, KyungMo; Cisar, Craig J. "Effects Of Kettlebell Training On Aerobic Capacity." Journal of Strength & Conditioning Research: Post Acceptance: January 5, 2015.
• Gillum, Trevor L.; Keunnen, Matthew R.; Castillo, Micaela N.; Williams, Williams Nicole L.; Jordan-Patterson, Alex T. "Exercise, but not acute sleep loss, increases salivary antimicrobial protein secretion." Journal of Strength & Conditioning Research: Post Acceptance: January 5, 2015.  
• Harry, John R.; Paquette, Max R.; Caia, Johnpaul; Townsend, Robert J.; Weiss, Lawrence W.; Schilling, Brian K. "The Effects of Footwear Condition on Maximal Jumping Performance." Journal of Strength & Conditioning Research: Post Acceptance: January 5, 2015. 
• Raeder, Christian; Fernandez-Fernandez, Jaime; Ferrauti, Alexander. "Effects of six weeks of medicine ball training on throwing velocity, throwing precision, and isokinetic strength of shoulder rotators in female handball players." Journal of Strength & Conditioning Research:
  Post Acceptance: January 5, 2015.