Smith, JC, Pridgeon, B, and Hall, MC. Acute effect of foam rolling and dynamic stretching on flexibility and jump height. J Strength Cond Res 32(8): 2209–2215, 2018—Dynamic stretching (DS) can acutely improve vertical jump (VJ) performance but its effect lasts no more than 5 minutes. Foam rolling (FR), a form of self-myofascial release, can acutely increase range of motion (ROM) with this effect lasting less than 10 minutes. Therefore, the purpose of this study was to evaluate the time course of these effects, separately and combined, on VJ height and ROM. Twenty-nine university students completed 4 different sessions (control, FR, DS, and combo) in a randomized order. After a warm-up and baseline assessments of VJ height and sit-and-reach, participants rested (control) and performed FR, DS, and the combination of FR and DS (combo). Vertical jump height and ROM were assessed every 5 minutes for 20 minutes after treatment. Mean scores at each time point were expressed as a percent change from baseline scores. Immediately after FR, sit-and-reach was significantly greater than control (p = 0.003). Vertical jump height immediately after treatment for DS and combo was significantly greater than the control and FR counterparts (p ≤ 0.002). Vertical jump height for DS and combo was also significantly greater than the control counterpart at 5 minutes after treatment (p < 0.001). At 15 minutes after treatment, the percent change in VJ height for the combo was significantly greater than the control counterpart (p = 0.002). Although FR has no effect on VJ performance, it can acutely increase ROM, but its effect was quickly dissipated. Foam rolling does not seem to enhance VJ height either alone or in combination with DS.

Purpose: In a rested state, foam rolling has been shown to improve blood flow to the working tissues. When inducing post-activation performance enhancement (PAPE), previous research suggests a longer recovery period between the conditioning activity and performance assessment in weaker participants (back squat <2.0 x body mass). It is possible that a cool-down effect may take place between the conditioning activity and performance assessment for these participants. Therefore, the purpose of this investigation was to determine if foam rolling could help mitigate any cool-down effect to help participants capitalize on PAPE. Methods: Seventeen physically active participants completed baseline jumps followed by rest (control), back squat exercise (heavy squats), rest and foam rolling (FR), and heavy squats followed by foam rolling (combo). VJ performance was assessed three times post-treatment with 2 min between each assessment. Results: VJ height and impulse were greater at baseline than at any other time point across all sessions (p < .001). Impulse for the control and FR sessions were greater than the squats session (p < .015). Impulse for the combo session was less than the FR session (p = .04). Conclusions: Foam rolling did not have a significant impact on attenuating any cool-down effect. In addition, our heavy squats protocol appears to induce too much fatigue that possibly masked the effects of PAPE.

Analyzing vertical jumps performed on a force plate can be useful for the strength and conditioning professional in managing neuromuscular fatigue. The purpose of this study was to compare different movement thresholds when analyzing countermovement (CJ) and squat jump (SJ) performance. Twenty-one college-aged participants (9 female, 12 male) performed five CJs and five SJs. Movement initiation was identified when the vertical ground reaction force (VGRF) deviated five standard deviations (5SD), four standard deviations, (4SD), 2.5% of system weight (2.5%SW), and 10% of system weight (10%SW) from their starting position. For CJs, movement was determined when the VGRF deviated either above or below these thresholds (5SDAB, 4SDAB, 2.5%SWAB, 10%SWAB) and was compared to when VGRF deviated below these thresholds (5SDB, 4SDB, 2.5%SWB, 10%SWB) in terms of peak force (Fmax), net impulse (netIMP), braking impulse (brIMP), propulsive impulse, jump height (JHT), peak power (Pmax), peak velocity (Vmax), and RSImod. For SJs, movement was determined when VGRF initially rose above these thresholds (5SD, 4SD, 2.5%SW, and 10%SW) for Fmax, netIMP, JHT, and Vmax. Significant differences were observed among several methods except for Fmax. However, these differences were small. All CJ measures demonstrated good-to-excellent relative reliability (ICC: 0.790–0.990) except for netIMP for 2.5%SWAB (ICC: 0.479). All methods demonstrated good absolute reliability as measured by percent coefficient of variation (CV%) except brIMP and RSImod. This may be due to instructions given to each jumper as well as skill level. For SJs, no differences in Fmax or netIMP were found across all methods. Small differences were seen for JHT, Pmax, and Vmax across several methods. All methods produced acceptable CV% (<10%) and excellent ICCs (0.900–0.990). However, some jumpers produced CV% that was greater than 10% when determining JHT for 5SD, 4SD, and 2.5%SW methods. This could be due to our method of obtaining system weight. Based on our findings, we recommend using the 10%SW method for assessing SJ performance on a force plate.

Countermovement vertical jumps (CMVJs) can be used for athletic monitoring. When performed on a force plate, biomechanical variables can be obtained to identify factors relating to performance. Commercially available software can be purchased to analyze metrics relating to CMVJs. Users are typically limited to metrics provided by these “black box” setups. However, some commercial products provide export functions for users to manipulate raw data. These programs often require additional components to complete the analysis, which could be cost prohibitive. The purpose of this article is to compare using Excel, MATLAB, R, and Python to analyze multiple CMVJ trials, so practitioners have more control over how metrics are determined rather than relying on the “black box” setup with or without the expense of third-party proprietary software. This guide will introduce Python by presenting a template for analyzing force plate jump data. Strategies for reading files, filtering data, calculating biomechanical variables, graphically representing data, and writing results to a master data file will be discussed. Although the provided script can be used to analyze CMVJ data by itself, it can be modified to include other metrics the practitioner wishes to include in their setting (see Supplemental Digital Content 1, http://links.lww.com/SCJ/A383).

The purpose of the study was to examine static postural control/balance in young adults with intellectual and developmental disabilities (IDD) and typically developing (TD) young adults before, during, and after an inclusive badminton intervention. Eight participants (four IDD-BADM and four TD-BADM) participated in a 12-week inclusive badminton intervention, with the other eight participants as matched controls (four IDD-CONTR and four TD-CONTR) (74.19 kg ± 9.8 kg, 171.96 cm ± 5.4 cm; 21.7 ± 1.8 years of age; nine females and seven males; eight with IDD and eight TD). The study followed a repeated measures design (pre, mid, post) before the intervention, at 6 weeks, and after 12 weeks. Static postural sway conditions included: bilateral stance eyes open (20 s), eyes closed (10 s), foam eyes open (20 s), foam eyes closed (10 s), and unilateral stance eyes open (10 s) and foam eyes open (10 s). Sway measurements included: average anterior/posterior (A/P) displacement (in), average medial/lateral (M/L) displacement (in), average 95% ellipsoid area (in²), and average velocity (ft/s). Significant time × group interactions were reported for average velocity (EO) (p = 0.030), average length (EO) (p = 0.030), 95% ellipsoid area (EO) (p = 0.049), and average A/P displacement (1LEO) (p = 0.036) for IDD-BADM. Significant time main effects were reported for average A/P displacement (FEO) (p = 0.040) for IDD groups. Significant time main effects were reported for average M/L displacement (EO) (p = 0.001), (EC) (p = 0.004), (FEO) (p = 0.005), (FEC) (p = 0.004), and average A/P displacement (EO) (p = 0.006) and (FEO) (p = 0.005) for TD groups. An inclusive badminton program indicated evidence of improved static postural control for those with IDD. However, no significant differences were reported for TD peers.