Sport-Specific Warm-Up Attenuates Static Stretching- Induced Negative Effects on Vertical Jump But Not Neuromuscular Excitability in Basketball Players.

The purpose of this study was to examine the acute effects of static stretching (SS) and dynamic stretching (DS), alone and in combination with specific basketball warm-up (SBWU), on the neuromuscular excitability and vertical jump height in basketball players. Twelve healthy young male basketball players participated in the study (18 ± 0.42 years; 17.4 - 18.6 age range; 188 ± 9 cm; 76.5 ± 9 kg). All participants completed two different stretching treatments (static and dynamic), performed on different days at least seven days apart, in the same period of training microcycle, in a counterbalanced order. Each session consisted of a self-paced jogging warm-up, followed by a 10-minute testing period (T0), which involved eliciting H reflex and M waves, followed by three trials of a vertical jump test. Participants then performed one of the treatment protocols. After another test (T1), participants conducted 8-minute specific basketball warm-up and then one more test (T2). Combined 3 (time) x 2 (stretching protocol) analysis of variance with repeated measures on both factors revealed that SS significantly decreased spinal excitability (H/M ratio) (p = 0.015, d = -0.38, percentage of change = -20.55%) and vertical jump height (p = 0.007, d = -1.91, percentage of change = -2.6%), but after SBWU, vertical jump height increased (p = 0.006, d = 1.13, percentage of change = 3.01%), while H/M ratio continued decreasing (p = 0.019, d = -0.45, percentage of change = -30.23%). Acute effects of DS, alone and in combination with SBWU were not significant. It seems that SBWU attenuates negative acute effects of SS on vertical jump performance in young basketball players, while DS appears to cause no significant acute effect for this population.

Transcranial application of near-infrared low-level laser can modulate cortical excitability.

BACKGROUND AND OBJECTIVE: Near-infrared low-level laser (NIR-LLL) irradiation penetrates scalp and skull and can reach superficial layers of the cerebral cortex. It was shown to improve the outcome of acute stroke in both animal and human studies. In this study we evaluated whether transcranial laser stimulation (TLS) with NIR-LLL can modulate the excitability of the motor cortex (M1) as measured by transcranial magnetic stimulation (TMS). METHODS: TLS was applied for 5 minutes over the representation of the right first dorsal interosseal muscle (FDI) in left primary motor cortex (M1), in 14 healthy subjects. Motor evoked potentials (MEPs) from the FDI, elicited by single-pulse TMS, were measured at baseline and up to 30 minutes after the TLS. RESULTS: The average MEP size was significantly reduced during the first 20 minutes following the TLS. The pattern was present in 10 (71.5%) of the participants. The MEP size reduction correlated negatively with the motor threshold at rest. CONCLUSIONS: TLS with NIR-LLL induced transitory reduction of the excitability of the stimulated cortex. These findings give further insights into the mechanisms of TLS effects in the human cerebral cortex, paving the way for potential applications of TLS in treatment of stroke and in other clinical settings.

Bilateral sequential motor cortex stimulation and skilled task performance with non-dominant hand.

OBJECTIVE: To check whether bilateral sequential stimulation (BSS) of M1 with theta burst stimulation (TBS), using facilitatory protocol over non-dominant M1 followed by inhibitory one over dominant M1, can improve skilled task performance with non-dominant hand more than either of the unilateral stimulations do. Both, direct motor cortex (M1) facilitatory non-invasive brain stimulation (NIBS) and contralateral M1 inhibitory NIBS were shown to improve motor learning. METHODS: Forty right-handed healthy subjects were divided into 4 matched groups which received either ipsilateral facilitatory (intermittent TBS [iTBS] over non-dominant M1), contralateral inhibitory (continuous TBS [cTBS] over dominant M1), bilateral sequential (contralateral cTBS followed by ipsilateral iTBS), or placebo stimulation. Performance was evaluated by Purdue peg-board test (PPT), before (T0), immediately after (T1), and 30min after (T2) an intervention. RESULTS: In all groups and for both hands, the PPT scores increased at T1 and T2 in comparison to T0, showing clear learning effect. However, for the target non-dominant hand only, immediately after BSS (at T1) the PPT scores improved significantly more than after either of unilateral interventions or placebo. CONCLUSION: M1 BSS TBS is an effective intervention for improving motor performance. SIGNIFICANCE: M1 BSS TBS seems as a promising tool for motor learning improvement with potential uses in neurorehabilitation.

Transcranial magnetic stimulation has no placebo effect on motor learning.

OBJECTIVE: Motor learning is the core cognitive function in neurorehabilitation and in various other skill-training activities (e.g. sport, music). Therefore, there is an increasing interest in the use of transcranial magnetic stimulation (TMS) methods for its enhancement. However, although usually assumed, a potential placebo effect of TMS methods on motor learning has never been systematically investigated. METHODS: Improvement of performance on the Purdue Pegboard Task over three test-blocks (T0, T1, and T2), separated by >20 min, was used to evaluate motor learning. In Experiment-1, two groups of 10 participants each were compared: one group immediately before T1 received a sham intermittent theta burst stimulation procedure (P-iTBS group), while another did not have any intervention at all (control - CON group). In Experiment-2, a third group of participants (six subjects) who received sham high-frequency repetitive TMS procedure before T1 (P-rTMS group) was compared with P-iTBS group. RESULTS: All three groups showed significant learning over time, but without any difference between them, either in Experiment-1 between P-iTBS and CON, or in Experiment-2 between P-rTMS and P-iTBS. CONCLUSION: The results suggest lack of any placebo effect of TMS on motor learning. SIGNIFICANCE: The results may help in designing further TMS-motor learning studies and in interpreting their results.