4.1.1 Sex-specific differences.

As commonly reported for other sports, sex-specific differences in the kinematics of fencing were identified [35, 43, 44]. Specifically, females exhibited greater hip adduction, knee abduction/adduction, ankle eversion and patellofemoral contact forces of the leading leg during lunging movements [30, 45]. Some researchers have proposed that sex-specific differences in anthropometrics, neuromuscular functions and muscle strength may account for these differences in the kinematics of the leading leg [35, 43, 44]. Overall, the prevalence of injury was higher in female fencers (29%-44%, averaged: 36%) than in males (22%-32%, averaged: 27%) [2]. However, further evidence is required to characterize sex-specific differences based on high-quality evidence.

4.1.2 Anthropometry and muscle strength.

The assessment of anthropometrics and strength is an important component for establishing functional profiles of fencers [46]. Performance of the lunge, considered to be the core component of fencing, was evaluated using stepping time or velocity, counter-movement jump strength and dynamometric tests [28, 47], with some studies evaluating the value of squat jump tests for predicting lunge performance [31, 34]. Despite differences in measurement, there is a consensus that greater lower limb strength and explosive power generated higher lunge velocity and quicker fencing moves [48, 49]. Ballistic training is therefore recommended to increase the rate of muscle force generation [50, 51], or a combination of resistance and ballistic training to optimize the explosive, power and endurance requirements of fencing [51, 52]. Turner et al. reported that most training programs were customized to a fencer’s ability, sex and age by coaches, based on their experience or anecdotal knowledge rather than on evidence. Turner et al. [53] advocated the need to develop evidence-based training protocols which would consider a fencer’s biomechanics, as well as physiological and psychological factors. Continued evaluation of the predictive value of somatotypes and measures of muscle strength and power to evaluate and improve fencing performance overall, and the lunge component more specifically, using multivariate analysis should be pursued in future studies.

4.1.3 Asymmetry.

Fencing is clearly an asymmetric sports event based on its kinematic and kinetics [3, 15, 18]. Intuitively, the asymmetric sports contributed to asymmetry anthropometry due to the unilateral nature of the training. Irurtia et al. and Turner et al. [26, 53] showed that fencers had significantly higher handgrip strength and greater isokinetic leg strength on the dominant side than on the non-dominant side. Margonato and colleagues [23] conducted surveys on national-level fencers and discovered that they had higher muscle cross-sectional area in the dominant forearm. Arm and leg asymmetries were also observed in young fencers [49]

However, the effects of laterality on measures of muscle structure and performance have not been always consistently reported. Poulis et al. [48] failing to identify differences in peak knee and ankle isokinetic torques between the dominant and nondominant lower limb. It was argued that fencing movements do not necessarily induce unequal muscle growth between two sides of the lower limb. In fact, both trailing and leading legs contributed significantly to the progression of various fencing actions, especially for advance and fleche [15, 24]. Besides, Akpinar et al. [38] investigated the differences in movement accuracy, speed, multi-joint coordination, and handedness between fencers and non-fencers in a series of hand reaching tasks. They showed that fencers may have performance symmetry superior to non-fencers due to an underlying high skill in bilateral control, while Poulis also advocated that elite fencers have all-round development on their neuromuscular system [48]. In fact, the risk of injury associated with asymmetry is recognized, such that balance or weight training is often introduced to tackle with possible asymmetry-induced injuries [54–56] [36, 57]. The variation in outcome measures and training method may contribute to the inconsistency of results. Therefore, the development and role of asymmetry in fencing should be subject of future studies.

4.2.1 Weapon.

Foil, saber, and epee are the three major weapons used in fencing sports. Each weapon has its own rules and strategies. Though the basic offensive and defensive techniques are universally applicable in the three weapons, their biomechanics may differ due to the variances in blade type (e.g. length and weight), valid target (e.g. torso with and without the extremities) and scoring technique (e.g. thrusting and cutting). Both epee and foil are thrusting weapons which score only by landing their tips on the valid area, while epee is heavier (775g VS 350-500g, same in blade length: 90cm) than foil. In spite of the limited evidence from existing studies, there was a trend in the numbers present that foil fencers had slightly higher peak velocity in mass center (1.92m/s VS 1.72m/s), weapon (2.91m/s VS 2.49m/s), and the front foot (4.56m/s VS 4.10m/s) than epee fencers during the execution of simple lunge attack [16, 18, 24, 25, 29, 33, 40–42]. Though the comparison is based on different samples, there are also signs from some performance analyses that the length of action and break was shorter in foil than in epee (5.2s VS 12.7s, 15.6s VS 18.2s) [14]. Ratio of action to break was lower in foil (1:3) than in epee (1:1.0–1.4) [1, 58], indicating quicker-finished bouts in foil. Saber (weight: 500g, length: 88cm in the blade) is most distinctive from the other two weapons by its ‘cutting’ rule. Data from research on saber biomechanics was rare, but saber was thought to have a fast tempo and a quicker burst of speed than the other two weapons [59]. Length of action/break (2.5±0.6s, 16.5±2.7s) and ratio of action to break (1:6.5) was the lowest in saber [14]. Up to date, fencing weapons were usually studies in simple movement and controlled in-lab conditions, e.g. lunge and fleche. However, in-game combat is more complex involving many extensions of the fundamental actions. Saber fencing may be even faster paced than reports.

In addition to having to bear the weight of the long weapon itself, fencers’ wrist further sustains abrupt and violent loading during the series of attack and defense fencing actions. Therefore, a well-designed weapon handle is important for reducing abnormal wrist joint motion and lowering the risk of wrist injury. Three types of handles are generally used in fencing: the French, the pistol, and the Italian handle. The French and Italian handles have evolved from the classical rapier handle from the Baroque period, with the French handle slightly contoured to the curve of the hand. The pistol handle is much like that of a pistol and commonly known as the “anatomical” or “orthopaedic” grip. Use of the pistol handle is advocated as it elicits lower activation in the adductor pollicis and extensor carpi radialis muscles compared to the French and Italian handles [22]. Moreover, the Visconti style pistol handle also promotes a more balanced activation of forearm muscles [21, 22] which would delay muscle fatigue and improve the capacity of the wrist to resists excessive motion when external forces are applied. This protective function of the pistol handle can be enhanced by placing the handle at an angle of 18°-21°, which also improves hit rate and accuracy while delaying the onset of early fatigue [21].

4.2.2 Footwear and the fencing piste.

Fencers’ feet are repeatedly exposed to large transient impact shock, especially during sudden forward thrusts, increasing the risk of lower limb injuries [60]. The metal carpet piste is the main source of these high impact forces. Although different overlay materials have been used for shock absorption, Greenhalgh et al. [27] could not confirm a significant attenuation of impact magnitude for different overlays.

Fencing shoes compound this problem by providing little intrinsic shock absorption, compared to standard court shoes. Geil [20] and Sinclair et al. [7] confirmed the lower shock absorption capacity of fencing shoes compared to squash and running shoes. Geil [20] did discuss the trade-off between increased shock absorption of shoes and a slower and less reliable performance, with shock absorbing materials reducing sensory information from the floor which provides important proprioceptive input for agility and balance [61]. Therefore, finding a balance between shock absorption and performance remains an issue to be resolved.

4.2.3 Training and conditioning.

The success of fencing was largely determined by speed and explosive strength [53]. Therefore, ballistic training is recommended to increase the rate of muscle force generation [62], with most of the improvements occurring within the first 200 to 300 milliseconds of a single lunge movement [63, 64]. Research has shown that pure fencing training regime did not induce growth of muscle strength that overrode the progression of puberty for the adolescent fencers (compared to the inactive children: increases in arm cross sectional area: 17.1% VS 6.97%, increases in grip strength: 25.81% VS 18.07%) [51]. The increases of leg muscle cross sectional area (32±7%) and body mass (16±3%) in fencers was also insignificant when the effects of body height were ruled out. The author thus recommended strength training for young fencers to complement their training routine.

Training of balance and coordination is also a fundamental element [65], By taking specific balance training, fencers demonstrated better coordination (42.36% improvement in balance score) and less body sway (7.02% less in dispersion of the center of plantar pressure) in single-leg standing tasks. When coordinating touché and lunge movements, elite fencers produced higher sword velocity (2.90±0.30m/s VS 2.52±0.29m/s) and body center velocity (0.41±0.20m/s VS 0.04±0.10m/s), compared to novice fencers [36, 40]. In their review of training programs, Turner et al. [53] reported that most programs are customized to a fencer’s ability, sex and age by coaches, based on their experience or anecdotal knowledge rather than on evidence. Turner et al. advocated the need to develop evidence-based training protocols which would consider a fencer’s biomechanics, as well as physiological and psychological factors.

4.3.1 Posture and kinematics.

In lunging, power during the propulsion phase is provided by the ankle plantarflexors and knee/hip extensors of the trailing leg, with additional contribution from the hip flexors and knee extensors of the leading leg during the subsequent flight phase [15]. Contrarily in fleche, both lower limbs provided power in a cyclical sprint-like manner. During the initial phase, the trailing leg provides the thrusting power as its ankle plantarflexors and knee extensors control the velocity of flexion at the ankle and knee joints of the leading leg. Once the trailing leg passes in front of the leading leg, the thrust-absorption cycle is repeated with a reversal of the power and absorption roles of the lower limbs [15]. Lower limb coordination and balance also significantly influence performance, with elite fencers generating greater hip flexion force of the leading leg at the end of a lunging movement and, hence, a higher sword velocity [16, 25]. Range of motion of the knee and peak hip flexion range of the trailing leg and hip flexion range of the leading leg were identified as significant predictors of lunge performance, allowing fencers to assume a low on-guard position and adjust movement of the leading leg in lunge to improve their performance [16]. Though these studies of fencing performance were based on small sample size, their subjects were mostly elite fencers who can represent the significance of fencing sports. Besides, the outcomes were quite consistent in terms of phase-contributors of lunge dynamics.

Study of in-shoe pressure revealed the asymmetric characteristics of weight bearing on the foot. Trautmann, Martinelli & Rosenbaum [3] and Geil [20] evaluated the distribution of plantar pressures during three fencing movements [3]. Load was predominantly placed on the heel of the leading foot and on the forefoot of the trailing foot during performance of a lunge and advance, with plantar pressure being a maximum under the hallux, bilaterally, during the retreat movement, regardless of the type of shoes worn. Steward and Kopetka [24] further reported time-to-peak angular velocity of the knee joint of the trailing leg and of the elbow of on the leading side to have a significant effect on overall lunge speed. The angle of the trailing foot relative to the lead foot also influenced lunge performance [68]. Gresham-Fieg, House & Zupan [32] evaluated the effects of three different angles of rear foot placement on lunge performance, confirming that placement of the rear foot perpendicular to the alignment of the forefoot produced higher magnitudes of peak and average power and average velocity of lunging.

4.3.2 Joint coordination and synergy.

The proximal-to-distal coupling of upper and lower limb motion ensures an effective transfer of joint segmental angular velocity of the lower limb to the maximum linear velocity of the center of mass [69], a feature which differentiates elite from novice fencers [37]. Elite fencers extended the weapon arm prior to initiating front foot movement during lunge [18]. Focusing specifically on the coordination among lower limb joints, Mulloy et al. [37] identified that elite fencers exhibited greater peak horizontal sword velocity and lunge distance in comparison to novice fencers through a clearly sequential increase in angular velocity of joint extension from the hip, to the knee, to the ankle. This kinematic sequence was claimed to be the correct technique that increase fencing success in elite fencers [39]. Do and Yiou has identified a ‘refractory period’ existing between motor tasks that had negative effects on fencing performance [42]. Elite fencers were competent to inhibit the effects by closely linking ‘touche’ movement of the arm and ‘lunge’ movement of the legs in perfect timeline [41]. Technical training should take into account of the specific fencing movement pattern, with emphasis on practicing different movement components in combination rather than in separate form [40].

4.3.3 Muscle coordination and synergy.

The proximal-to-distal sequence was also reported for muscle activation, with activation of the anterior deltoid of the armed upper limb, with extension of the armed hand, preceding the lifting of the lead foot at the initiation of lunging in expert fencers [40]. In contrast, novice fencers exhibited a delayed onset of upper limb muscle activity, associated with shortened propulsion phase by the trailing leg resulting in an earlier “kick off” of the trailing leg in novice fencers [18, 67]. Overall, elite fencers presented more coherent muscle synergies of the upper and lower limbs, compared to novice fencers, characterized by sequential activation of shoulder/elbow extensors of the armed upper limb and hip/knee extensors of the rear lower limb, followed by activation of the forelimb during lunging, with the ability to maintain this quasi-invariant pattern of activation despite changing task requirements during a fencing bout [39, 67]. In contrast, muscle activation patterns for novice fencers were more variable with changing task demands imposed by their opponents, often leading to interruptions in their movement [29, 33]. Therefore, novice fencers may not have consolidated neuromuscular strategies for complex, multi-segmental movements [70], while elite fencers are able to finely adjust muscle activation patterns to optimize attacking (lunge) efficiency without violating the “correct” kinematic sequence of upper and lower limb motions (as the sequence mentioned in section 4.3.2: rear knee extension-front shoulder extension-front knee extension-front knee flexion) [17].