A shaping frame designed to equip a shoulder strap (8a, 8b) of a load, the shoulder strap (8a, 8b) being adapted, in use, to being installed at the level of a shoulder (12, 15) and a support surface of a wearer, the shaping frame having one same inner surface (Si) and one same outer surface (Se) and comprising: -- an upper frame portion located, in use, at the level of the shoulder (12, 15), when the shoulder strap (8a, 8b) equipped with the shaping frame is installed on the shoulder (12, 15) of the wearer, -- a front frame portion which extends the upper frame portion, which front frame portion extends downwards, the front frame portion comprising a support portion shaped such that, in use, the support portion bears against a support surface of the wearer when the shoulder strap (8a, 8b) equipped with the shaping frame bears against the support surface of the wearer, the upper frame portion and the front frame portion, the inner surface (Si) of the shaping frame having the shape of a Moebius strip portion, which inner surface (Si) is, in use, oriented towards the support surface of the wearer the shaping frame being characterized in that the shape of the inner surface (Si) of the shaping frame is geometrically defined by the following features: - the inner surface (Si) is caused by a continuous rotation of a segment about its middle, the length of said segment corresponds to the width of said inner surface, and - the middle of said segment describes a trajectory describing a curve, and - the continuous rotation is non-zero and in the same direction, along said trajectory, - the curve described by the trajectory being a left curve selected from a helix portion (Tf), or a rational sextic portion (Tg), or a non-rational sextic portion (Th). -- an upper frame portion located, in use, at the level of the shoulder (12, 15), when the shoulder strap (8a, 8b) equipped with the shaping frame is installed on the shoulder (12, 15) of the wearer, -- a front frame portion which extends the upper frame portion, which front frame portion extends downwards, the front frame portion comprising a support portion shaped such that, in use, the support portion bears against a support surface of the wearer when the shoulder strap (8a, 8b) equipped with the shaping frame bears against the support surface of the wearer, the upper frame portion and the front frame portion, the inner surface (Si) of the shaping frame having the shape of a Moebius strip portion, which inner surface (Si) is, in use, oriented towards the support surface of the wearer the shaping frame being characterized in that the shape of the inner surface (Si) of the shaping frame is geometrically defined by the following features: - the inner surface (Si) is caused by a continuous rotation of a segment about its middle, the length of said segment corresponds to the width of said inner surface, and - the middle of said segment describes a trajectory describing a curve, and - the continuous rotation is non-zero and in the same direction, along said trajectory, - the curve described by the trajectory being a left curve selected from a helix portion (Tf), or a rational sextic portion (Tg), or a non-rational sextic portion (Th). - the inner surface (Si) is caused by a continuous rotation of a segment about its middle, the length of said segment corresponds to the width of said inner surface, and - the middle of said segment describes a trajectory describing a curve, and - the continuous rotation is non-zero and in the same direction, along said trajectory, - the curve described by the trajectory being a left curve selected from a helix portion (Tf), or a rational sextic portion (Tg), or a non-rational sextic portion (Th).