Background: There are a myriad of exercise variations in which upper body (UB) and lower body (LB) exercises have been intermittently used. However, it is still unclear how training of one body region (e.g. LB) affects adaptations in distant body areas (e.g. UB), and how different UB and LB exercise configurations could help facilitate physiological adaptations of either region; both referred to in this review as vertical strength transfer. Objective: We aimed to investigate the existence of the vertical strength transfer phenomenon as a response to various UB and LB exercise configurations and to identify potential mechanisms underpinning its occurrence. Methods: A systematic search using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) for Scoping Reviews protocol was conducted in February 2024 using four databases (Web of Science, MEDLINE, Scopus and CINAHL) to identify peer-reviewed articles that investigated the vertical strength transfer phenomenon. Results: Of the 5242 identified articles, 24 studies met the inclusion criteria. Findings suggest that the addition of UB strength training to LB endurance exercise may help preserve power-generating capacity for the leg muscle fibres. Furthermore, systemic endocrine responses to high-volume resistance exercise may beneficially modulate adaptations in precedingly or subsequently trained muscles from a different body region, augmenting their strength gains. Last, strength training for LB could result in improved strength of untrained UB, likely due to the increased central neural drive. Conclusions: Vertical strength transfer existence is enabled by neurophysiological mechanisms. Future research should involve athletic populations, examining the potential of vertical strength transfer to facilitate athletic performance and preserve strength in injured extremities.

Purpose: To investigate the influence of upper body (UB) strength qualities and UB strength training on the performance of high-intensity running and jumping actions and to identify gaps and recommendations for future research. Methods: A systematic search using the PRISMA Scoping Review protocol was conducted in February 2024 using PubMed, Scopus, and ICTRP. Studies eligible for inclusion were those that reported associations between UB or trunk maximal strength qualities (e.g., absolute strength, forces, power) and high-intensity running or jumping actions or investigated the influence of an isolated UB strength training intervention on high-intensity running or jumping performances. Results: Of the 4730 articles, 7 studies met the inclusion criteria, reporting correlations for 16 high-intensity running or jumping tests. No intervention studies were identified. Preliminary findings of the limited number of studies highlight that greater UB maximal strength-generating capacity may positively influence repeated sprint ability. While a significant moderate correlation between greater absolute UB strength and faster “flying” sprint was also reported, mixed results were found for sprint acceleration. There is also evidence that change-of-direction performance may greatly benefit from high maximal isometric strength of all trunk muscles and that strong trunk extensors may enhance drop jumps. Conclusions: This review identifies the potential of UB strength to contribute to high-intensity running and jumping actions. Future research is warranted to investigate this link via various UB strength tests and UB strength training protocols aimed at maximising neuromuscular adaptations.

It is currently unclear how personal fitness training (PT) clients in Serbia evaluate this service and what motivates them to be consistent with the training practice in the quest for obtaining physical literacy and health outcomes. A cross-sectional explorative study was used to investigate consumers' perceptions on the PT service with the aim to inform trainers on clients' motivational factors, challenges and experiences in the pursuit of training goals. A total of 148 respondents completed the anonymous questionnaire via Qualtrics platform. The key findings of the study can be summarised as follows: 1) PT clients in Serbia are using up these services primarily for sustained exercise adherence and motivation to attain and maintain health-related goals, 2) PT clients in Serbia highly value professional dedication of a personal trainer as well as their ability to facilitate supportive social environment, 3) Personal trainers in Serbia are expected to play a significant role in motivating clients, especially those with weight management needs and limited capacity for self-directed lifestyle changes. Additionally, there is a need for increased transparency from fitness centres regarding the qualifications of employed trainers and their backgrounds. Stakeholders should find a way to encourage PT consumers to provide feedback and express their impressions more effectively, thereby reducing the chances of losing the motivation to hire or keep a personal trainer. In conclusion, PT clients in Serbia value holistic training practices and expect their personal trainers to lead them and motivate them to reach the targeted health-related objectives.

Background/Objectives: To evaluate the intraday and interday reliability of seated horizontal upper body (UB) isometric push and pull tests performed with the VALD DynaMo Max dynamometer. Methods: Fifty-two recreationally active individuals (41 men, 11 women; 25.0 ± 6.1 years) completed two sessions 48 h apart, each comprising three maximal-effort push and pull trials at 90° elbow flexion using a custom-built rig with the attached dynamometer. Peak force (PF), peak rate of force development (RFD), impulse, and time-to-PF were extracted from 1200 Hz force–time data. Reliability was assessed using the intraclass correlation coefficient (ICC), coefficient of variation (CV%), standard error of measure (SEM) and minimal detectable change (MDC). Results: PF demonstrated excellent reliability (ICC = 0.97–0.99) with low absolute error (CV < 6%; MDC = 128–149 N). Impulse showed good-to-excellent reliability (ICC = 0.90–0.94; CV < 10%; MDC ≈ 755–790 N·s), whereas RFD displayed good reliability but greater variability (ICC = 0.80–0.81; CV < 20%; MDC = 2574–2925 N·s⁻¹). Time-to-PF was the least reliable (ICC = 0.68–0.71; CV > 24%; MDC = 1.5–1.7 s). Conclusions: Horizontal isometric push and pull tests using the VALD DynaMo Max dynamometer provide reliable measures of PF and impulse for athlete profiling and tracking substantial longitudinal changes. Peak RFD may be cautiously used for broad cross-sectional comparisons, although its higher variability limits precision in distinguishing smaller inter-individual differences and appears less sensitive to within-individual changes. Time-to-PF demonstrated insufficient reliability for practical application.

This study aimed to investigate the perception of soccer strength and conditioning (S&C) coaches on the importance of upper body (UB) strength training for the performance of high-intensity actions (HIA) (i.e., sprinting, repeated sprint ability, change of direction, and jumping) in professional soccer players, and to identify current practices with regards to UB strength testing and training methodologies within this sport. Eighty-six S&C coaches working with professional soccer players volunteered to complete the survey. Twenty-two fixed responses and three open-ended questions were grouped into three sections: (a) demographic information, (b) perspectives on the importance of UB strength and UB strength training for HIA, and (c) current practices of UB strength training in soccer. Frequency analysis was used to assess fixed response questions, and thematic analysis established clear and recognisable themes for open-ended questions. Relative to “not important” options, UB strength was perceived as important for all HIA, especially for jumping (89%) and acceleration (87%). Coaches strongly supported the idea that UB strength plays a role in enhancing HIA, with particular influence on jumping (100%), acceleration (97%) and COD (93%). This positive influence is believed to be realised via improved force transmissions (97%) and neural drive (94%). Notably, however, surveyed coaches overwhelmingly use moderate resistance in their sessions (100%) without substantial emphasis on high-velocity contractions (64%). In conclusion, S&C practitioners value UB strength training for enhancing the performance of HIA in professional soccer players. Further research is needed to explore this link and provide clearer guidance on the implementation of UB strength training in professional soccer.

(1) Background: Handgrip strength (HGS) is a widely used indicator of neuromuscular function, with predictive values for health and performance outcomes. The aim of this study was to evaluate the intraday and interday reliability of maximal and explosive handgrip force–time metrics using the Kinvent K-Grip handheld dynamometer. (2) Methods: Thirty-four participants performed three maximal voluntary isometric contractions per hand across two testing days. Force–time data were analysed for peak force (PF), mean force (MF), peak rate of force development (RFD), time-specific RFD, impulse, and forces at fixed time points. Reliability was assessed using intraclass correlation coefficients (ICCs), standard error of measurement (SEM), minimal detectable change (MDC), and coefficient of variation (CV%). (3) Results: The device demonstrated excellent relative and absolute reliability for PF and MF across both days (ICC > 0.97; CV < 6%; MDC ≈ 5 kg). Later-phase explosive metrics (F250 and Imp200) showed good-to-excellent relative reliability (ICC = 0.88-0.99; CV = 4–14%), although with variable absolute reliability (MDC F250 ≈ 4–8 kg, MDC Imp200 ≈ 1 kg·s). For early-phase metrics, relative reliability was only moderate to good (ICC = 0.67–0.88) and characterised by a high degree of variability (CV = 15–22%). (4) Conclusions: The K-Grip handheld dynamometer is a reliable tool for cross-sectional assessments and for tracking larger maximal strength and later-phase force improvements at fixed time points. Early-phase explosive metrics are less suitable for monitoring intervention effects due to high measurement error and fatigue sensitivity.