Effects of upper and lower body wearable resistance on spatio-temporal and kinetic parameters during running

Acute locomotor, heart rate and neuromuscular responses to added wearable resistance during soccer-specific training

PURPOSE

Investigate acute locomotor, internal (heart rate (HR) and ratings of perceived exertion (RPE)) and neuromuscular responses to using wearable resistance loading for soccer-specific training.

METHODS

Twenty-six footballers from a French 5th division team completed a 9-week parallel-group training intervention (intervention group: n = 14, control: n = 12). The intervention group trained with wearable resistance (200-g on each posterior, distal-calf) for full-training sessions on Day + 2, D + 4 and unloaded on D + 5. Between-group differences in locomotor (GPS) and internal load were analyzed for full-training sessions and game simulation drills. Neuromuscular status was evaluated using pre- and post-training box-to-box runs. Data were analyzed using linear mixed-modelling, effect size ±90% confidence limits (ES ± 90%CL) and magnitude-based decisions.

RESULTS

Full-training sessions: Relative to the control, the wearable resistance group showed greater total distance (ES [lower, upper limits]: 0.25 [0.06, 0.44]), sprint distance (0.27 [0.08, 0.46]) and mechanical work (0.32 [0.13, 0.51]). Small game simulation (<190 m2/player): wearable resistance group showed small decreases in mechanical work (0.45 [0.14, 0.76]) and moderately lower average HR (0.68 [0.02, 1.34]). Large game simulation (>190 m2/player): no meaningful between-group differences were observed for all variables. Training induced small to moderate neuromuscular fatigue increases during post-training compared to pre-training box-to-box runs for both groups (Wearable resistance: 0.46 [0.31, 0.61], Control: 0.73 [0.53, 0.93]).

CONCLUSION

For full training, wearable resistance induced higher locomotor responses, without affecting internal responses. Locomotor and internal outputs varied in response to game simulation size. Football-specific training with wearable resistance did not impact neuromuscular status differently than unloaded training.

The use of wearable resistance and weighted vest for sprint performance and kinematics: a systematic review and meta-analysis

Wearable resistance (WR) and weighted vests (WV) can be used in almost all training conditions to enhance sprint performance; however, positioning and additional mass are different in WV and WR strategies, affecting performance and kinematics differently. We aimed to systematically review the literature, searching for intervention studies that reported the acute or chronic kinematic and performance impact of WV and WR and comparing them. We analyzed Pubmed, Embase, Scopus, and SPORTDiscuss databases for longitudinal and cross-over studies investigating sprint performance or kinematics using an inverse-variance with a random-effect method for meta-analysis. After the eligibility assessment, 25 studies were included in the meta-analysis. Cross-over WR and WV studies found significantly higher sprint times and higher ground contact times (CT) compared to unloaded (UL) conditions. However, WR presented a lower step frequency (SF) compared to UL, whereas WV presented a lower step length (SL). Only one study investigated the chronic adaptations for WR, indicating a superiority of the WR group on sprint time compared to the control group. However, no difference was found chronically for WV regarding sprint time, CT, and flight time (FT). Our findings suggest that using WV and WR in field sports demonstrates overload sprint gesture through kinematic changes, however, WR can be more suitable for SF-reliant athletes and WV for SL-reliant athletes. Although promising for chronic performance improvement, coaches and athletes should carefully consider WV and WR use since there is no supporting evidence that WV or WR will impact sprint performance, CT, and FT.

Effects of Different Wearable Resistance Placements on Running Stability

Stability during running has been recognized as a crucial factor contributing to running performance. This study aimed to investigate the effects of wearable equipment containing external loads on different body parts on running stability. Fifteen recreational male runners (20.27 ± 1.23 years, age range 19-22 years) participated in five treadmill running conditions, including running without loads and running with loads equivalent to 10% of individual body weight placed on four different body positions: forearms, lower legs, trunk, and a combination of all three (forearms, lower legs, and trunk). A tri-axial accelerometer-based smartphone sensor was attached to the participants' lumbar spine (L5) to record body accelerations. The largest Lyapunov exponent (LyE) was applied to individual acceleration data as a measure of local dynamic stability, where higher LyE values suggest lower stability. The effects of load distribution appear in the mediolateral (ML) direction. Specifically, running with loads on the lower legs resulted in a lower LyE_ML value compared to running without loads (p = 0.001) and running with loads on the forearms (p < 0.001), trunk (p = 0.001), and combined segments (p = 0.005). These findings suggest that running with loads on the lower legs enhances side-to-side local dynamic stability, providing valuable insights for training.

Acute changes in acceleration phase sprint biomechanics with lower body wearable resistance

The aim of this acute cross-sectional study was to quantify the kinematic and kinetic changes that occur during sprint acceleration when lower body WR is worn. Fifteen male rugby athletes (19 years; 181 cm; 91 kg) were assessed during maximal effort over-ground and treadmill sprinting over 20 m under three different loading conditions: 0%, 3% and 5% body mass (BM) added weight attached to the lower body. Treadmill data provided a convenient estimate of kinetic changes in the absence of in-ground force plates. The loaded conditions resulted in significantly increased ground contact time (5 to 6%) and decreased step frequency (-2 to -3%) during sprint accelerations (effect size = 0.32-0.72). Moderate WR loading (3% BM) resulted in increased (9%; effect size = 0.66) theoretical maximum horizontal force (relative to BM) and unchanged 20 m sprint times (p > 0.05). Heavier WR loading (5% BM) resulted in a significant decrease (-4%) in vertical ground reaction forces (relative to total system mass) and slower (1 to 2%) 20 m sprint times (effect size = 0.38-0.70). Lower body WR loading up to 5% BM can provide specific sprint training overload, while affecting sprint acceleration biomechanics by ≤ 6%.

Effects of different hydration supports on stride kinematics, comfort, and impact accelerations during running

BACKGROUND

Different supports for hydration can influence total body mass and affect running biomechanics.

RESEARCH QUESTION

Do different hydration supports affect the perceived exertion and comfort, stride kinematics, and impact accelerations during running?

METHODS

This was a crossover study design. Thirteen trail runners completed a treadmill running test divided into four different durations and randomized hydration supports conditions, lasting 8 min each at moderate intensity: A) waist bag (0.84 kg); B) medium load backpack (0.84 kg); C) full load backpack (3.40 kg); and D) a control condition without water support. Impact accelerations were measured for 30 s in 4, 6, and 8 min. The rate of perceived exertion and heart rate were registered on minutes 4 and 8. At the last minute of each condition, comfort perception was registered RESULTS AND SIGNIFICANCE: No condition affected the stride kinematics. Full load backpack condition reduced head acceleration peak (-0.21 g; p = 0.04; ES=0.4) and head acceleration magnitude (-0.23 g; p = 0.03; ES=0.4), and increased shock attenuation (3.08 g; p = 0.04; ES=0.3). It also elicited higher perceived exertion (p < 0.05; ES>0.8) being considered heavier (p < 0.01; ES > 1.1). The waist bag condition was more comfortable in terms of noise (p = 0.006; ES=1.3) and humidity/heat (p = 0.001; ES=0.8). The waist bag was the most comfortable support. On the other hand, the full backpack elicited lower comfort and was the only generating compensatory adjustments. These results may help to improve design of full load backpack aiming at comfort for runners.

The assessment of a novel lower body resistance garment as a mechanism to increase the training stimulus during running: a randomised cross-over study

Background

This study examined the physiological and perceived impact of wearing a novel lower body resistance garment during exercise and recovery.

Methods

Using a randomised cross-over design, 15 recreationally-active males performed 2 × 10-min steady-state runs followed by a 10-min passive recovery with concomitant monitoring of oxygen consumption (V̇O₂), heart rate (HR) and rating of perceived exertion (RPE; exercise portion only), wearing either the resistance garment (experimental) or running shorts (control).

Results

During exercise, there was a trend for V̇O₂ and RPE to be higher (4.5% and 7.7% respectively) in experimental than control (V̇O₂: r = 0.24, p > 0.05; RPE: r = 0.32, p > 0.05) and for HR to be lower (− 0.4%, r = − 0.05, p > 0.05). During recovery, V̇O₂ and HR tended to be lower (4.7% and 4.3% respectively) in experimental than control (V̇O₂: r = − 0.32, p > 0.05; HR: r = − 0.27, p > 0.05).

Conclusions

Though effects were trivial to small, and not statistically significant, these findings provide proof of concept and suggest that this garment design may increase the training stimulus during running and aid post-exercise recovery.

Kinetic and Kinematic Effects of Asymmetrical Loading of the Lower Limb During High-Speed Running

CONTEXT

Light lower-limb wearable resistance has little effect on running biomechanics. However, asymmetrical wearable resistance may potentially alter the kinetics and kinematics of high speed, enabling greater loading or unloading of an injured or rehabilitative lower limb.

DESIGN

A cross-sectional study design was used to quantify the influence of asymmetric calf loading on the kinematics and kinetics during 90% maximum sprinting velocity.

METHODS

Following a familiarization session, 12 (male = 7 and female = 5) physically active volunteers ran at 90% of maximal velocity. In random order, participants ran with zero (0) wearable resistance and with loads of 300 g (L300) and 600 g (L600) fixed to one shank. A nonmotorized treadmill quantified vertical and horizontal kinetics and step kinematics. The kinetics and kinematics of the loaded (L0, L300, and L600) and unloaded (UL; UL0, UL300, and UL600) limbs were compared.

RESULTS

Vertical step ground reaction force of the loaded limb tended to increase between unloaded and 300 and 600 conditions (effect size [ES] = 0.48 to 0.76, all P ≤ .12), while the horizontal step force of the UL tended to decrease (ES = 0.54 to 1.32, all P ≤ .09) with greater external loading. Step length increased in the UL in 0 versus 300 and 600 conditions (ES = 0.60 to 0.70, all P ≤ .06). Step frequency decreased in the ULs in unloaded versus 300 and 600 conditions (ES = 0.73 to 1.10, all P ≤ .03). Mean step velocity tended to be greater in the ULs than the 300 and 600 conditions (ES = 0.52 to 1.01, all P ≤ .10). Only 4 of 16 variables were significantly different between the 300 and 600 conditions.

CONCLUSIONS

Asymmetrical shank resistance could be used during high-speed running to reduce or increase the kinetic loading of an injured/rehabilitative limb during return to play protocols. Asymmetrical wearable resistance could also be used to alter step kinematics in runners with known asymmetries. Finally, meaningful alterations in high-speed running biomechanics can be achieved with only 300 g of shank loading.

Effects of lower limb light-weight wearable resistance on running biomechanics

Wearable resistance allows individualized loading for sport specific movements and can lead to specific strength adaptations benefiting the athlete. The objective was to determine biomechanical changes during running with lower limb light-weight wearable resistance. Fourteen participants (age: 28 ± 4 years; height: 180 ± 8 cm; body mass: 77 ± 6 kg) wore shorts and calf sleeves of a compression suit allowing attachment of light loads. Participants completed four times two mins 20-m over-ground shuttle running bouts at 3.3 m*s^-1 alternated by three mins rest. The first running bout was unloaded and the other three bouts were under randomised loaded conditions (1%, 3% and 5% additional loading of the individual body mass). 3D motion cameras and force plates recorded kinematic and kinetic data at the midpoint of each 20-m shuttle. Friedman-test for repeated measures and linear mixed effect model analysis were used to determine differences between the loading conditions (α = 0.05). Increased peak vertical ground reaction force (2.7 N/kg to 2.74 N/kg), ground contact time (0.20 s to 0.21 s) and decreased step length (1.49 m to 1.45 m) were found with additional 5 % body mass loading compared to unloaded running (0.001 > p < 0.007). Marginally more knee flexion and hip extension and less plantarflexion was seen with higher loading. Differences in the assessed parameters were present between each loading condition but accompanied by subject variability. Further studies, also examining long term effects, should be conducted to further inform use of this training tool.