Acute effects of unilateral and bilateral conditioning activity on countermovement jump, linear speed, and muscle stiffness: A randomized crossover study.

PurposeEvidence directly comparing the effects of bilateral and unilateral conditioning activities is limited. Therefore, the aim of this study was to assess the acute effect of unilateral and bilateral conditioning activity on vastus lateralis stiffness, countermovement jump parameters, and 10 m sprint.MethodsTwelve semi-professional basketball players participated in this study (age: 23 ± 4 yrs; body mass: 84.7 ± 10.6 kg; body height: 192 ± 6 cm; basketball training experience: 11 ± 4 yrs) performed four experimental sessions to compare the acute effects of bilateral, stronger-only, weaker-only lower limb or no conditioning activity on vastus lateralis stiffness, countermovement jumps variables (height; peak velocity; peak force, contraction time, countermovement depth, and modified reactive strength index and 10 m sprint time. Measurements were performed 5 minutes before and in the 5th and 10th minutes after CA.ResultsBilateral conditioning activity significantly increase the countermovement jump height (p = 0.002; ES = 0.71) and the reactive strength index modified (p = 0.010; ES = 0.59). Moreover, a significantly higher peak force in the stronger than in the weaker limb was found (p0.05). However, there were no significant (p>0.05) interactions and effects of conditions or time-point in the case of the other countermovement jump variables, vastus lateralis stiffness, and 10m sprint time.ConclusionUnilateral and bilateral drop jumps (3 sets of 5 repetitions) did not affect the vastus lateralis stiffness and time of the 10m sprint. However, only bilateral drop jumps effectively enhanced the countermovement jump height and modified reactive strength index. Bilateral drop jumps might be a useful part of a warm-up to improve jumping performance in basketball players

Using smartphones in the evaluation of spinal curvatures in a sagittal plane

Introduction: In physiotherapeutic diagnostic processes, various tools and methods may be used. However, price and availability may limit their daily use in clinical practice. Therefore, the suggestion that smartphones with specific applications may be useful as diagnostic tools can be found in the literature. However, before using them in clinical practice, it is important to verify their reliability. The aim of the study was to evaluate the consistency of measurements of the curvatures in the sagittal plane performed with the Saunders digital inclinometer and a smartphone application

Correction: Muscle strength, muscle power and body composition in college-aged young women and men with Generalized Joint Hypermobility.

[This corrects the article DOI: 10.1371/journal.pone.0236266.]

Effects of whole-body vibration warm-up on subsequent jumping and running performance

Abstract The aim of this study was to examine whether acute whole-body vibration, a single bout of drop jumps, or a combination of both may enhance countermovement jump (CMJ) and would affect volitional pace 3 km running performance. Twelve healthy and recreationally active males completed 4 conditions in randomized order: (i) 5 sets of 30 s calf raises on the platform but without vibration; (ii) 5 sets of 30 s calf raises on the vibration platform with 30 s rest intervals between sets; (iii) 5 sets of 6 drop jump with a 30 s rest interval between sets; (iv) 5 sets of 30 s calf raises on the vibration platform followed by 6 drop jumps with a 30 s rest interval between sets. Before, 3-min after, and immediately after a 3 km run each participant performed CMJ. No significant difference between conditions (p = 0.327) for the 3 km time trial was found. Whereas CMJ height and relative peak power were significantly improved in post-3 km run than at baseline (p < 0.001 and p = 0.025) and post-warm-up (p = 0.001 and p = 0.002) in all conditions. The present study indicates that warm-up consisting of either whole-body vibration, drop jumps, or a combination of both failed to acutely improve CMJ and 3 km volitional pace running performance in physically active males. However, the increase in the CMJ performance was noted after the end of the 3 km run, which may indicate that the warm-up protocols used were insufficient to enhance subsequent performance

Muscle strength, muscle power and body composition in college-aged young women and men with Generalized Joint Hypermobility.

The aim of this study was an evaluation of the musculoskeletal system in women and men with Generalized Joint Hypermobility (GJH). The study included 87 participants- 40 with Generalized Joint Hypermobility (aged 21.2 ±1.8 years) and 47 (aged 21.0 ±1.3 years) in the control group (CG). The study included the Beighton score, the measurements of body composition, muscle flexibility (Straight Leg Raise test, Popliteal Angle test, Modified Thomas Test), and the measurements of muscle strength and muscle power. T-test and Mann-Whitney U Test were applied to assess the differences between independent groups. The study showed that there were no significant differences (p>.05) in the assessed body composition and the muscle flexibility between both women and men with GJH and the participants in the CG. Under isokinetic conditions for the non-dominant lower extremity, men from the CG received significantly higher (p = .02) flexion peak torque at 180°/s angular velocity. Women from the CG received a statistically significantly lower (p = .04) F/E ratio at 180°/s velocity. Under isometric conditions for both women and men with GJH, there were no statistically significant differences (p>.05) in the maximum torques in knee extension and flexion compared to the CG. For women and men with GJH, the maximum power in the lower extremities and jumping ability were not significantly different (p>.05) compared to the CG participants. The body composition, muscle flexibility, muscle strength, and muscle power of adults with Generalized Joint Hypermobility did not differ compared to healthy participants. The fact that there are no differences does not exclude the efficacy of strength training in increasing levels of muscle strength and its impact on body posture and proprioception or coordination

Acute Effects of Percussive Massage Treatment on Drop Jump Performance and Achilles Tendon Stiffness

This study aimed to investigate the impact of Achilles tendon (AT) mechanical percussion massage (PM) on the passive stiffness of that tendon and subsequent drop jump kinematics. Eleven physically active participants performed two conditions in random order: (i) 60 s of PM applied to each AT (EXP) and (ii) no PM (CTRL). Measurements were performed 5 min before, immediately after, and 5 min following the completion of the PM. In the CTRL, measurements were performed at the same time point but no massage was applied. The two-way ANOVA indicated that there was no statistically significant interaction effect on contact time (p = 0.786), reactive strength index (p = 0.914), and relative peak power (p = 0.896). However, a statistically significant interaction on peak velocity (p = 0.046) and jump height (p = 0.03) was found. Despite that, there was no significant post-hoc comparisons for jump height, it slightly decreased 5 min post-PM (p = 0.136; ES = &minus;0.25; &Delta; = &minus;3.1%) compared with the CTRL condition (p = 1.00; ES = 0.11; &Delta; = +1.5%). Friedman&rsquo;s test did not show significant differences in dominant (p = 0.073) and non-dominant limb (p = 0.091) AT stiffness. Although not significant, numerically, the dominant limb AT (p = 0.126; ES = &minus;0.64; &Delta; = &minus;7.8%) had a larger reduction in stiffness immediately post-PM compared with the non-dominant limb (p = 0.294; ES = &minus;0.26; &Delta; = &minus;3.6%). The results of this study indicated the temporary effect of PM on the reduction in tissue stiffness. Moreover, these findings show that a mechanical PM might slightly hinder subsequent explosive athletic performance

Intersession reliability of the analyzed variables.

Intersession reliability of the analyzed variables.</p

Comparison of inter-limb asymmetry.

B-CA–bilateral conditioning activity condition; S-CA–stronger limb conditioning activity condition; W-CA–weaker limb conditioning activity condition; CTRL–control condition.</p

Comparison of peak landing forces during particular conditioning activities.

S-CA–stronger limb conditioning activity condition; W-CA–weaker limb conditioning activity condition; B-CA bilateral conditioning activity. a–significant difference in comparison to other conditions; b–significant difference in comparison to the weaker limb during bilateral conditioning activity.</p